Transmitting/receiving system and method of processing broadcast signal in transmitting/receiving system

ABSTRACT

An apparatus and method for transmitting digital broadcast signal are provided. The apparatus includes a group formatter to format a data group including mobile service data, where the group formatter further maps the mobile service data into a data group of interleaved format, adds N training sequences into a corresponding location of the data group of interleaved format, adds signaling data into the data group of interleaved format, inserts place holder bytes for MPEG header and non-systematic Reed-Solomon (RS) parity into the data group of interleaved format, and deinterleaves the mobile service data in the data group of interleaved format, a non-systematic RS encoder to non-systematic RS encode the mobile service data in the formatted data group and insert non-systematic RS parity obtained from the non-systematic RS encoding into the formatted data group.

This application is a continuation of U.S. application Ser. No.12/613,918, filed Nov. 6, 2009, now U.S. Pat. No. 8,121,232, whichpursuant to 35 U.S.C. §119(a) claims the benefit of U.S. ProvisionalApplication No. 61/111,733, filed on Nov. 6, 2008, and U.S. ProvisionalApplication No. 61/112,192, filed on Nov. 7, 2008, the contents of allof which are hereby incorporated by reference as if fully set forthherein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital broadcasting system fortransmitting and receiving digital broadcast signal, and moreparticularly, to a transmitting system for processing and transmittingdigital broadcast signal, and a receiving system for receiving andprocessing digital broadcast signal and, a method of processing data inthe transmitting system and the receiving system.

2. Discussion of the Related Art

The Vestigial Sideband (VSB) transmission mode, which is adopted as thestandard for digital broadcasting in North America and the Republic ofKorea, is a system using a single carrier method. Therefore, thereceiving performance of the digital broadcast receiving system may bedeteriorated in a poor channel environment. Particularly, sinceresistance to changes in channels and noise is more highly required whenusing portable and/or mobile broadcast receivers, the receivingperformance may be even more deteriorated when transmitting mobileservice data by the VSB transmission mode.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a transmitting systemand a receiving system and a method of processing broadcast signal thatsubstantially obviate one or more problems due to limitations anddisadvantages of the related art.

An object of the present invention is to provide a transmitting systemand a receiving system and a method of processing broadcast signal thatare highly resistant to channel changes and noise.

Another object of the present invention is to provide a transmittingsystem and a receiving system and a method of processing broadcastsignal that can enhance the receiving performance of the receivingsystem by performing additional encoding on mobile service data and bytransmitting the processed data to the receiving system.

A further object of the present invention is to provide a transmittingsystem and a receiving system and a method of processing broadcastsignal that can also enhance the receiving performance of the receivingsystem by inserting known data already known in accordance with apre-agreement between the receiving system and the transmitting systemin a predetermined region within a data region.

A further object of the present invention is to provide a transmittingsystem and a receiving system and a method of processing broadcastsignal that can enhanced the receiving performance of the receivingsystem, by using the known data so as to perform channel equalization,therein the known data are inserted in a data region and then received.

Another object of the present invention is to provide a receiving systemand method for processing a broadcast signal that can enhancechannel-equalizing performance by estimating a channel impulse response(CIR) of a general data section located between training sections usingcubic spline interpolation, in performing channel-equalization usingtraining sequences that are inserted in data regions and receivedaccordingly.

A further object of the present invention is to provide a receivingsystem and method for processing a broadcast signal that can enhancechannel-equalizing performance by estimating a channel impulse response(CIR) of a general data section located outside of the training sectionsusing extrapolation, in performing channel-equalization using trainingsequences that are inserted in data regions and received accordingly.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, adigital broadcast transmitting system may include a service multiplexerand a transmitter. The service multiplexer may multiplex mobile servicedata and main service data at a predetermined data rate and may transmitthe multiplexed data to the transmitter. The transmitter may performadditional encoding on the mobile service data being transmitted fromthe service multiplexer. The transmitter may also group a plurality ofadditionally encoded mobile service data packets so as to form a datagroup. The transmitter may multiplex mobile service data packetsincluding mobile service data and main service data packets includingmain service data and may transmit the multiplexed data packets to areceiving system.

Herein, the data group may be divided into a plurality of regionsdepending upon a degree of interference of the main service data. Also,a long known data sequence may be periodically inserted in regionswithout interference of the main service data. Also, a receiving systemaccording to an embodiment of the present invention may be used fordemodulating and channel equalizing the known data sequence.

In another aspect of the present invention, a receiving system includesa signal receiving unit, a detector, a channel equalizer, a blockdecoder, and an error correction unit. The signal receiving unitreceives a broadcast signal including mobile service data and a datagroup including N number of training sequences. The detector detects Nnumber of training sequences from the broadcast signal (wherein N≧5),wherein the detected N number of training sequences are received duringN number of training sections. The equalizer estimates a channel impulseresponse (CIR) of N number of training sections, based upon the detectedN number of training sequences, applies the channel impulse responseestimated in M number of training sections (wherein N≧M) to a cubicspline interpolation function, so as to generate a channel impulseresponse of (N−1) number of mobile service data sections located betweenthe N number of training sections, thereby performingchannel-equalization on the mobile service data of the correspondingmobile service data section. The block decoder performs turbo-decodingin block units on the channel-equalized mobile service data. And, theerror correction unit performs error correction decoding on theturbo-decoded mobile service data, thereby correcting errors occurringin the mobile service data.

Herein, each of the N number of training sequences may be located atconstant intervals within the data group. The data group that is beingreceived may correspond to one of a data group including fieldsynchronization data and a data group not including any fieldsynchronization data. More specifically, in the data group includingfield synchronization data, N may be equal to 6, and 6 trainingsequences may correspond to 1 field synchronization data sequence and 5known data sequences. And, in data group not including any fieldsynchronization data, N may be equal to 5, and 5 training sequences maycorrespond to 5 known data sequences.

The equalizer may apply channel impulse responses (CIRs) estimated in 5training sections to each cubic spline interpolation function of (N−1)number of mobile service data sections, so as to generate a CIR for eachmobile service data section.

When the mobile service data are not located between training sections,the equalizer may generate a CIR of an extrapolation section includingthe mobile service data by applying channel impulse responses (CIRs)estimated in at least 2 training sections to an extrapolation function,and may perform channel-equalization on the mobile service data of theextrapolation section. Herein, the equalizer may compensate a power of aCIR of the extrapolation section, so that a proportional relationbetween a power of a signal and the compensated power of the CIR bothmeasured in the extrapolation section can become identical to aproportional relation between a power of a signal and a power of a CIRboth measured in at least one training section.

In a further aspect of the present invention, a broadcast signalprocessing method in a digital broadcast receiving system includes thesteps of receiving a broadcast signal including mobile service data anda data group including N number of training sequences, detecting Nnumber of training sequences from the broadcast signal (wherein N≧5),the detected N number of training sequences being received during Nnumber of training sections, estimating a channel impulse response (CIR)of N number of training sections, based upon the detected N number oftraining sequences, applying the channel impulse response estimated in Mnumber of training sections (wherein N≧M) to a cubic splineinterpolation function, so as to generate a channel impulse response of(N−1) number of mobile service data sections located between the Nnumber of training sections, thereby performing channel-equalization onthe mobile service data of the corresponding mobile service datasection, performing turbo-decoding in block units on thechannel-equalized mobile service data, and performing error correctiondecoding on the turbo-decoded mobile service data, thereby correctingerrors occurring in the mobile service data.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a structure of a M/H frame for transmitting andreceiving mobile service data according to the present invention;

FIG. 2 illustrates an exemplary structure of a VSB frame;

FIG. 3 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in aspace region;

FIG. 4 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in atime region;

FIG. 5 illustrates an alignment of data after being data interleaved andidentified;

FIG. 6 illustrates an enlarged portion of the data group shown in FIG. 5for a better understanding of the present invention;

FIG. 7 illustrates an alignment of data before being data interleavedand identified;

FIG. 8 illustrates an enlarged portion of the data group shown in FIG. 7for a better understanding of the present invention;

FIG. 9 illustrates an exemplary assignment order of data groups beingassigned to one of 5 sub-frames according to the present invention;

FIG. 10 illustrates an example of assigning a single parade to an M/Hframe according to the present invention;

FIG. 11 illustrates an example of assigning 3 parades to an M/H frameaccording to the present invention;

FIG. 12 illustrates an example of expanding the assignment process of 3parades to 5 sub-frames within an M/H frame;

FIG. 13 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted;

FIG. 14 illustrates a block diagram showing a general structure of atransmitting system according to an embodiment of the present invention;

FIG. 15 is a diagram illustrating an example of RS frame according tothe present invention;

FIG. 16 is a diagram illustrating a structure of an M/H header within anM/H service data packet according to the present invention;

FIG. 17( a) and FIG. 17( b) are diagrams illustrating another example ofRS frame according to the present invention; and

FIG. 18 illustrates a block diagram showing an example of a servicemultiplexer of FIG. 14;

FIG. 19 illustrates a block diagram showing an embodiment of atransmitter of FIG. 14;

FIG. 20 illustrates a block diagram showing an example of apre-processor of FIG. 19;

FIG. 21 illustrates a conceptual block diagram of the M/H frame encoderof FIG. 20;

FIG. 22 illustrates a detailed block diagram of an RS frame encoder ofFIG. 21;

FIG. 23( a) and FIG. 23( b) illustrate a process of one or two RS framebeing divided into several portions, based upon an RS frame mode value,and a process of each portion being assigned to a corresponding regionwithin the respective data group;

FIG. 24( a) to FIG. 24( c) illustrate error correction encoding anderror detection encoding processes according to an embodiment of thepresent invention;

FIG. 25( a) to FIG. 25( d) illustrate an example of performing a rowpermutation (or interleaving) process in super frame units according tothe present invention;

FIG. 26( a) and FIG. 26( b) illustrate an example which a paradeconsists of two RS frames

FIG. 27( a) and FIG. 27( b) illustrate an exemplary process of dividingan RS frame for configuring a data group according to the presentinvention;

FIG. 28 illustrates a block diagram of a block processor according to anembodiment of the present invention;

FIG. 29 illustrates a detailed block diagram of a convolution encoder ofthe block processor;

FIG. 30 illustrates a symbol interleaver of the block processor;

FIG. 31 illustrates a block diagram of a group formatter according to anembodiment of the present invention;

FIG. 32 illustrates a block diagram of a trellis encoder according to anembodiment of the present invention;

FIG. 33 illustrates an example of assigning signaling information areaaccording to an embodiment of the present invention;

FIG. 34 illustrates a detailed block diagram of a signaling encoderaccording to the present invention;

FIG. 35 illustrates an example of a syntax structure of TPC dataaccording to the present invention;

FIG. 36 illustrates an example of a transmission scenario of the TPCdata and the FIC data level according to the present invention;

FIG. 37 illustrates an example of power saving of in a receiver whentransmitting 3 parades to an M/H frame level according to the presentinvention;

FIG. 38 illustrates an example of a training sequence at the byte levelaccording to the present invention;

FIG. 39 illustrates an example of a training sequence at the symbolaccording to the present invention;

FIG. 40 illustrates a block diagram of a receiving system according toan embodiment of the present invention;

FIG. 41 is a block diagram showing an example of a demodulating unit inthe receiving system;

FIG. 42 is a block diagram showing an example of an operation controllerof FIG. 41;

FIG. 43 illustrates an example of linear interpolation according to thepresent invention;

FIG. 44 illustrates the relation between a segment and a channel impulseresponse (CIR) in a data group including field synchronization dataaccording to the present invention;

FIG. 45 illustrates the relation between a segment and a channel impulseresponse (CIR) in a data group not including any field synchronizationdata according to the present invention;

FIG. 46 illustrates the relation between a segment and a channel impulseresponse (CIR) in a data group, which is used for estimating the CIR ofa general data section located between training sections, among datasections including field synchronization data according to the presentinvention;

FIG. 47 illustrates an example of linear extrapolation according to thepresent invention;

FIG. 48 illustrates the relation between a power of a CIR and a signalpower in a data group including field synchronization data according tothe present invention;

FIG. 49 illustrates a block diagram of a channel equalizer according toan embodiment of the present invention;

FIG. 50 illustrates a block diagram of a block decoder according to anembodiment of the present invention;

FIG. 51( a) and FIG. 51( b) illustrate an exemplary process ofconfiguring one or two RS frame by collecting a plurality of portionsaccording to the present invention;

FIG. 52 and FIG. 53 illustrate process steps of error correctiondecoding according to an embodiment of the present invention;

FIG. 54 to FIG. 61 illustrate an exemplary of a data group formatrepresented using numbers before (prior) data interleaving according tothe present invention;

FIG. 62 to FIG. 72 illustrate an exemplary of a data group formatrepresented using numbers before (prior) data interleaving according tothe present invention;

FIG. 73 illustrates an example of a training sequence represented usingnumbers at the byte level according to the present invention; and

FIG. 74 illustrates an example of a training sequence represented usingnumbers at the symbol according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. In addition,although the terms used in the present invention are selected fromgenerally known and used terms, some of the terms mentioned in thedescription of the present invention have been selected by the applicantat his or her discretion, the detailed meanings of which are describedin relevant parts of the description herein. Furthermore, it is requiredthat the present invention is understood, not simply by the actual termsused but by the meaning of each term lying within.

Among the terms used in the description of the present invention, mainservice data correspond to data that can be received by a fixedreceiving system and may include audio/video (A/V) data. Morespecifically, the main service data may include A/V data of highdefinition (HD) or standard definition (SD) levels and may also includediverse data types required for data broadcasting. Also, the known datacorrespond to data pre-known in accordance with a pre-arranged agreementbetween the receiving system and the transmitting system.

Additionally, among the terms used in the present invention, “M/H (orMH)” corresponds to the initials of “mobile” and “handheld” andrepresents the opposite concept of a fixed-type system. Furthermore, theM/H service data may include at least one of mobile service data andhandheld service data, and will also be referred to as “mobile servicedata” for simplicity. Herein, the mobile service data not onlycorrespond to M/H service data but may also include any type of servicedata with mobile or portable characteristics. Therefore, the mobileservice data according to the present invention are not limited only tothe M/H service data.

The above-described mobile service data may correspond to data havinginformation, such as program execution files, stock information, and soon, and may also correspond to A/V data. Most particularly, the mobileservice data may correspond to A/V data having lower resolution andlower data rate as compared to the main service data. For example, if anA/V codec that is used for a conventional main service corresponds to aMPEG-2 codec, a MPEG-4 advanced video coding (AVC) or scalable videocoding (SVC) having better image compression efficiency may be used asthe A/V codec for the mobile service. Furthermore, any type of data maybe transmitted as the mobile service data. For example, transportprotocol expert group (TPEG) data for broadcasting real-timetransportation information may be transmitted as the main service data.

Also, a data service using the mobile service data may include weatherforecast services, traffic information services, stock informationservices, viewer participation quiz programs, real-time polls andsurveys, interactive education broadcast programs, gaming services,services providing information on synopsis, character, background music,and filming sites of soap operas or series, services providinginformation on past match scores and player profiles and achievements,and services providing information on product information and programsclassified by service, medium, time, and theme enabling purchase ordersto be processed. Herein, the present invention is not limited only tothe services mentioned above.

In the present invention, the transmitting system provides backwardcompatibility in the main service data so as to be received by theconventional receiving system. Herein, the main service data and themobile service data are multiplexed to the same physical channel andthen transmitted.

Furthermore, the transmitting system according to the present inventionperforms additional encoding on the mobile service data and inserts thedata already known by the receiving system and transmitting system(e.g., known data), thereby transmitting the processed data.

Therefore, when using the transmitting system according to the presentinvention, the receiving system may receive the mobile service dataduring a mobile state and may also receive the mobile service data withstability despite various distortion and noise occurring within thechannel.

M/H Frame Structure

In the embodiment of the present invention, the mobile service data arefirst multiplexed with main service data in M/H frame units and, then,modulated in a VSB mode and transmitted to the receiving system.

At this point, one M/H frame consists of K1 number of sub-frames,wherein one sub-frame includes K2 number of slots. Also, each slot maybe configured of K3 number of data packets. In the embodiment of thepresent invention, K1 will be set to 5, K2 will be set to 16, and K3will be set to 156 (i.e., K1=5, K2=16, and K3=156). The values for K1,K2, and K3 presented in this embodiment either correspond to valuesaccording to a preferred embodiment or are merely exemplary. Therefore,the above-mentioned values will not limit the scope of the presentinvention.

FIG. 1 illustrates a structure of an M/H frame for transmitting andreceiving mobile service data according to the present invention. In theexample shown in FIG. 1, one M/H frame consists of 5 sub-frames, whereineach sub-frame includes 16 slots. In this case, the M/H frame accordingto the present invention includes 5 sub-frames and 80 slots. Also, in apacket level, one slot is configured of 156 data packets (i.e.,transport stream packets), and in a symbol level, one slot is configuredof 156 data segments. Herein, the size of one slot corresponds to onehalf (½) of a VSB field. More specifically, since one 207-byte datapacket has the same amount of data as a data segment, a data packetprior to being interleaved may also be used as a data segment.

At this point, two VSB fields are grouped to form a VSB frame.

FIG. 2 illustrates an exemplary structure of a VSB frame, wherein oneVSB frame consists of 2 VSB fields (i.e., an odd field and an evenfield). Herein, each VSB field includes a field synchronization segmentand 312 data segments.

The slot corresponds to a basic time period for multiplexing the mobileservice data and the main service data. Herein, one slot may eitherinclude the mobile service data or be configured only of the mainservice data.

If one M/H frame is transmitted during one slot, the first 118 datapackets within the slot correspond to a data group. And, the remaining38 data packets become the main service data packets. In anotherexample, when no data group exists in a slot, the corresponding slot isconfigured of 156 main service data packets.

Meanwhile, when the slots are assigned to a VSB frame, an offset existsfor each assigned position.

FIG. 3 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in aspace region. And, FIG. 4 illustrates a mapping example of the positionsto which the first 4 slots of a sub-frame are assigned with respect to aVSB frame in a time region.

Referring to FIG. 3 and FIG. 4, a 38^(th) data packet (TS packet #37) ofa 1^(st) slot (Slot #0) is mapped to the 1^(st) data packet of an oddVSB field. A 38^(th) data packet (TS packet #37) of a 2^(nd) slot (Slot#1) is mapped to the 157^(th) data packet of an odd VSB field. Also, a38^(th) data packet (TS packet #37) of a 3^(rd) slot (Slot #2) is mappedto the 1^(st) data packet of an even VSB field. And, a 38^(th) datapacket (TS packet #37) of a 4^(th) slot (Slot #3) is mapped to the157^(th) data packet of an even VSB field. Similarly, the remaining 12slots within the corresponding sub-frame are mapped in the subsequentVSB frames using the same method.

Meanwhile, one data group may be divided into at least one or morehierarchical regions. And, depending upon the characteristics of eachhierarchical region, the type of mobile service data being inserted ineach region may vary. For example, the data group within each region maybe divided (or categorized) based upon the receiving performance.

In an example given in the present invention, a data group is dividedinto regions A, B, C, and D in a data configuration after datainterleaving.

FIG. 5 illustrates an alignment of data after being data interleaved andidentified. FIG. 6 illustrates an enlarged portion of the data groupshown in FIG. 5 for a better understanding of the present invention.FIG. 7 illustrates an alignment of data before being data interleavedand identified. And, FIG. 8 illustrates an enlarged portion of the datagroup shown in FIG. 7 for a better understanding of the presentinvention. More specifically, a data structure identical to that shownin FIG. 5 is transmitted to a receiving system. In other words, one datapacket is data-interleaved so as to be scattered to a plurality of datasegments, thereby being transmitted to the receiving system. FIG. 5illustrates an example of one data group being scattered to 170 datasegments. At this point, since one 207-byte packet has the same amountof data as one data segment, the packet that is not yet processed withdata-interleaving may be used as the data segment.

FIG. 5 shows an example of dividing a data group prior to beingdata-interleaved into 10 M/H blocks (i.e., M/H block (B1) to M/H block10 (B10)). In this example, each M/H block has the length of 16segments. Referring to FIG. 5, only the RS parity data are allocated toa portion of 5 segments before the M/H block 1 (B1) and 5 segmentsbehind the M/H block 10 (B10). The RS parity data are excluded inregions A to D of the data group.

More specifically, when it is assumed that one data group is dividedinto regions A, B, C, and D, each M/H block may be included in any oneof region A to region D depending upon the characteristic of each M/Hblock within the data group. At this point, according to an embodimentof the present invention, each M/H block may be included in any one ofregion A to region D based upon an interference level of main servicedata.

Herein, the data group is divided into a plurality of regions to be usedfor different purposes. More specifically, a region of the main servicedata having no interference or a very low interference level may beconsidered to have a more resistant (or stronger) receiving performanceas compared to regions having higher interference levels. Additionally,when using a system inserting and transmitting known data in the datagroup, wherein the known data are known based upon an agreement betweenthe transmitting system and the receiving system, and when consecutivelylong known data are to be periodically inserted in the mobile servicedata, the known data having a predetermined length may be periodicallyinserted in the region having no interference from the main service data(i.e., a region wherein the main service data are not mixed). However,due to interference from the main service data, it is difficult toperiodically insert known data and also to insert consecutively longknown data to a region having interference from the main service data.

Referring to FIG. 5, M/H block 4 (B4) to M/H block 7 (B7) correspond toregions without interference of the main service data. M/H block 4 (B4)to M/H block 7 (B7) within the data group shown in FIG. 5 correspond toa region where no interference from the main service data occurs. Inthis example, a long known data sequence is inserted at both thebeginning and end of each M/H block. In the description of the presentinvention, the region including M/H block 4 (B4) to M/H block 7 (B7)will be referred to as “region A (=B4+B5+B6+B7)”. As described above,when the data group includes region A having a long known data sequenceinserted at both the beginning and end of each M/H block, the receivingsystem is capable of performing equalization by using the channelinformation that can be obtained from the known data. Therefore, thestrongest equalizing performance may be yielded (or obtained) from oneof region A to region D.

In the example of the data group shown in FIG. 5, M/H block 3 (B3) andM/H block 8 (B8) correspond to a region having little interference fromthe main service data. Herein, a long known data sequence is inserted inonly one side of each M/H block B3 and B8. More specifically, due to theinterference from the main service data, a long known data sequence isinserted at the end of M/H block 3 (B3), and another long known datasequence is inserted at the beginning of M/H block 8 (B8). In thepresent invention, the region including M/H block 3 (B3) and M/H block 8(B8) will be referred to as “region B(=B3+B8)”. As described above, whenthe data group includes region B having a long known data sequenceinserted at only one side (beginning or end) of each M/H block, thereceiving system is capable of performing equalization by using thechannel information that can be obtained from the known data. Therefore,a stronger equalizing performance as compared to region C/D may beyielded (or obtained).

Referring to FIG. 5, M/H block 2 (B2) and M/H block 9 (B9) correspond toa region having more interference from the main service data as comparedto region B. A long known data sequence cannot be inserted in any sideof M/H block 2 (B2) and M/H block 9 (B9). Herein, the region includingM/H block (B2) and M/H block 9 (B9) will be referred to as “regionC(=B2+B9)”. Finally, in the example shown in FIG. 5, M/H block 1 (B1)and M/H block 10 (B10) correspond to a region having more interferencefrom the main service data as compared to region C. Similarly, a longknown data sequence cannot be inserted in any side of M/H block 1 (B1)and M/H block 10 (B10).

Herein, the region including M/H block 1 (B1) and M/H block 10 (B10)will be referred to as “region D (=B1+B10)”. Since region C/D is spacedfurther apart from the known data sequence, when the channel environmentundergoes frequent and abrupt changes, the receiving performance ofregion C/D may be deteriorated.

FIG. 7 illustrates a data structure prior to data interleaving. Morespecifically, FIG. 7 illustrates an example of 118 data packets beingallocated to a data group. FIG. 7 shows an example of a data groupconsisting of 118 data packets, wherein, based upon a reference packet(e.g., a 1st packet (or data segment) or 157^(th) packet (or datasegment) after a field synchronization signal), when allocating datapackets to a VSB frame, 37 packets are included before the referencepacket and 81 packets (including the reference packet) are includedafterwards.

In other words, with reference to FIG. 5, a field synchronization signalis placed (or assigned) between M/H block 2 (B2) and M/H block 3 (B3).Accordingly, this indicates that the slot has an off-set of 37 datapackets with respect to the corresponding VSB field.

FIG. 54 to FIG. 61 illustrate an exemplary data group format representedusing numbers before (prior) data interleaving. In FIG. 54 to FIG. 61,the 207 variable bytes of each 208-byte MPEG-2 transport stream packetare shown. The initial MPEG-2 sync byte of each packet is not shown.Referring to FIG. 54 to FIG. 61, number 0 corresponds to main servicedata (i.e., normal VSB data), number 1 corresponds to signaling data (orsignling bytes or signaling information), number 2 corresponds to dummydata bytes, number 3 corresponds to trellis initialization bytes, number4 corresponds to MPEG header, number 5 corresponds to known (training)data sequence, number 6 corresponds to mobile service data (i.e., M/HData), and number 9 corresponds to RS parity bytes.

FIG. 62 to FIG. 72 illustrate an exemplary data group format representedusing numbers after data interleaving. In FIG. 62 to FIG. 72, the 207variable bytes of each 208-byte MPEG-2 transport stream packet areshown. The initial MPEG-2 sync byte of each packet is not shown. In adata group containing a field synchronization segment, the fieldsyncronization segment shall be inserted between data group segments #36and #37; i.e., 37 data group segments precede a data fieldsyncronization segment. Referring to FIG. 62 to FIG. 72, number 0corresponds to main service data (i.e., normal VSB data), number 1corresponds to signaling data (or signling bytes or signalinginformation), number 2 corresponds to dummy data bytes, number 3corresponds to trellis initialization bytes, number 4 corresponds toMPEG header, number 5 corresponds to known (training) data sequence,number 6 corresponds to mobile service data (i.e., M/H Data), and number9 corresponds to RS parity bytes.

The size of the data groups, number of hierarchical regions within thedata group, the size of each region, the number of M/H blocks includedin each region, the size of each M/H block, and so on described aboveare merely exemplary. Therefore, the present invention will not belimited to the examples described above.

FIG. 9 illustrates an exemplary assignment order of data groups beingassigned to one of 5 sub-frames, wherein the 5 sub-frames configure anM/H frame. For example, the method of assigning data groups may beidentically applied to all M/H frames or differently applied to each M/Hframe. Furthermore, the method of assigning data groups may beidentically applied to all sub-frames or differently applied to eachsub-frame. At this point, when it is assumed that the data groups areassigned using the same method in all sub-frames of the correspondingM/H frame, the total number of data groups being assigned to an M/Hframe is equal to a multiple of ‘5’.

According to the embodiment of the present invention, a plurality ofconsecutive data groups is assigned to be spaced as far apart from oneanother as possible within the M/H frame. Thus, the system can becapable of responding promptly and effectively to any burst error thatmay occur within a sub-frame.

For example, when it is assumed that 3 data groups are assigned to asub-frame, the data groups are assigned to a 1^(st) slot (Slot #0), a5^(th) slot (Slot #4), and a 9^(th) slot (Slot #8) in the sub-frame,respectively. FIG. 9 illustrates an example of assigning 16 data groupsin one sub-frame using the above-described pattern (or rule). In otherwords, each data group is serially assigned to 16 slots corresponding tothe following numbers: 0, 8, 4, 12, 1, 9, 5, 13, 2, 10, 6, 14, 3, 11, 7,and 15. Equation 1 below shows the above-described rule (or pattern) forassigning data groups in a sub-frame.j=(4i+0) mod 16  Equation 1Herein,

-   -   0=0 if i<4,    -   0=2 else if i<8,    -   0=1 else if i<12,    -   0=3 else.

Herein, j indicates the slot number within a sub-frame.

The value of j may range from 0 to 15 (i.e., 0≦j≦15). Also, value of iindicates the data group number. The value of i may range from 0 to 15(i.e., 0≦j≦15).

In the present invention, a collection of data groups included in an M/Hframe will be referred to as a “parade”. Based upon the RS frame mode,the parade transmits data of at least one specific RS frame.

The mobile service data within one RS frame may be assigned either toall of regions A/B/C/D within the corresponding data group, or to atleast one of regions A/B/C/D. In the embodiment of the presentinvention, the mobile service data within one RS frame may be assignedeither to all of regions A/B/C/D, or to at least one of regions A/B andregions C/D. If the mobile service data are assigned to the latter case(i.e., one of regions A/B and regions C/D), the RS frame being assignedto regions A/B and the RS frame being assigned to regions C/D within thecorresponding data group are different from one another.

In the description of the present invention, the RS frame being assignedto regions A/B within the corresponding data group will be referred toas a “primary RS frame”, and the RS frame being assigned to regions C/Dwithin the corresponding data group will be referred to as a “secondaryRS frame”, for simplicity. Also, the primary RS frame and the secondaryRS frame form (or configure) one parade. More specifically, when themobile service data within one RS frame are assigned either to all ofregions A/B/C/D within the corresponding data group, one paradetransmits one RS frame. In this case, also the RS frame will be referredto as a “primary RS frame”. Conversely, when the mobile service datawithin one RS frame are assigned either to at least one of regions A/Band regions C/D, one parade may transmit up to 2 RS frames.

More specifically, the RS frame mode indicates whether a paradetransmits one RS frame, or whether the parade transmits two RS frames.Table 1 below shows an example of the RS frame mode.

TABLE 1 RS frame mode (2 bits) Description 00 There is only one primaryRS frame for all group regions 01 There are two separate RS frames.Primary RS frame for group regions A and B Secondary RS frame for groupregions C and D 10 Reserved 11 Reserved

Table 1 illustrates an example of allocating 2 bits in order to indicatethe RS frame mode. For example, referring to Table 1, when the RS framemode value is equal to ‘00’, this indicates that one parade transmitsone RS frame. And, when the RS frame mode value is equal to ‘01’, thisindicates that one parade transmits two RS frames, i.e., the primary RSframe and the secondary RS frame. More specifically, when the RS framemode value is equal to ‘01’, data of the primary RS frame for regionsA/B are assigned and transmitted to regions A/B of the correspondingdata group. Similarly, data of the secondary RS frame for regions C/Dare assigned and transmitted to regions C/D of the corresponding datagroup.

As described in the assignment of data groups, the parades are alsoassigned to be spaced as far apart from one another as possible withinthe sub-frame. Thus, the system can be capable of responding promptlyand effectively to any burst error that may occur within a sub-frame.

Furthermore, the method of assigning parades may be identically appliedto all sub-frames or differently applied to each sub-frame. According tothe embodiment of the present invention, the parades may be assigneddifferently for each M/H frame and identically for all sub-frames withinan M/H frame. More specifically, the M/H frame structure may vary by M/Hframe units. Thus, an ensemble rate may be adjusted on a more frequentand flexible basis.

FIG. 10 illustrates an example of multiple data groups of a singleparade being assigned (or allocated) to an M/H frame. More specifically,FIG. 10 illustrates an example of a plurality of data groups included ina single parade, wherein the number of data groups included in asub-frame is equal to ‘3’, being allocated to an M/H frame. Referring toFIG. 10, 3 data groups are sequentially assigned to a sub-frame at acycle period of 4 slots. Accordingly, when this process is equallyperformed in the 5 sub-frames included in the corresponding M/H frame,15 data groups are assigned to a single M/H frame. Herein, the 15 datagroups correspond to data groups included in a parade. Therefore, sinceone sub-frame is configured of 4 VSB frame, and since 3 data groups areincluded in a sub-frame, the data group of the corresponding parade isnot assigned to one of the 4 VSB frames within a sub-frame.

For example, when it is assumed that one parade transmits one RS frame,and that a RS frame encoder located in a later block performsRS-encoding on the corresponding RS frame, thereby adding 24 bytes ofparity data to the corresponding RS frame and transmitting the processedRS frame, the parity data occupy approximately 11.37% (=24/(187+24)×100)of the total code word length. Meanwhile, when one sub-frame includes 3data groups, and when the data groups included in the parade areassigned, as shown in FIG. 10, a total of 15 data groups form an RSframe. Accordingly, even when an error occurs in an entire data groupdue to a burst noise within a channel, the percentile is merely 6.67%(=1/15×100). Therefore, the receiving system may correct all errors byperforming an erasure RS decoding process. More specifically, when theerasure RS decoding is performed, a number of channel errorscorresponding to the number of RS parity bytes may be corrected. Bydoing so, the receiving system may correct the error of at least onedata group within one parade. Thus, the minimum burst noise lengthcorrectable by a RS frame is over 1 VSB frame.

Meanwhile, when data groups of a parade are assigned as described above,either main service data may be assigned between each data group, ordata groups corresponding to different parades may be assigned betweeneach data group. More specifically, data groups corresponding tomultiple parades may be assigned to one M/H frame.

Basically, the method of assigning data groups corresponding to multipleparades is very similar to the method of assigning data groupscorresponding to a single parade. In other words, data groups includedin other parades that are to be assigned to an M/H frame are alsorespectively assigned according to a cycle period of 4 slots.

At this point, data groups of a different parade may be sequentiallyassigned to the respective slots in a circular method. Herein, the datagroups are assigned to slots starting from the ones to which data groupsof the previous parade have not yet been assigned.

For example, when it is assumed that data groups corresponding to aparade are assigned as shown in FIG. 10, data groups corresponding tothe next parade may be assigned to a sub-frame starting either from the12^(th) slot of a sub-frame. However, this is merely exemplary. Inanother example, the data groups of the next parade may also besequentially assigned to a different slot within a sub-frame at a cycleperiod of 4 slots starting from the 3^(rd) slot.

FIG. 11 illustrates an example of transmitting 3 parades (Parade #0,Parade #1, and Parade #2) to an M/H frame. More specifically, FIG. 11illustrates an example of transmitting parades included in one of 5sub-frames, wherein the 5 sub-frames configure one M/H frame.

When the 1^(st) parade (Parade #0) includes 3 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘0’ to ‘2’ for i in Equation 1. Morespecifically, the data groups of the 1^(st) parade (Parade #0) aresequentially assigned to the 1^(st), 5^(th), and 9^(th) slots (Slot #0,Slot #4, and Slot #8) within the sub-frame. Also, when the 2^(nd) paradeincludes 2 data groups for each sub-frame, the positions of each datagroups within the sub-frames may be obtained by substituting values ‘3’and ‘4’ for i in Equation 1.

More specifically, the data groups of the 2^(nd) parade (Parade #1) aresequentially assigned to the 2^(nd) and 12^(th) slots (Slot #3 and Slot#11) within the sub-frame.

Finally, when the 3^(rd) parade includes 2 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘5’ and ‘6’ for i in Equation 1. Morespecifically, the data groups of the 3^(rd) parade (Parade #2) aresequentially assigned to the 7^(th) and 11^(th) slots (Slot #6 and Slot#10) within the sub-frame.

As described above, data groups of multiple parades may be assigned to asingle M/H frame, and, in each sub-frame, the data groups are seriallyallocated to a group space having 4 slots from left to right. Therefore,a number of groups of one parade per sub-frame (NOG) may correspond toany one integer from ‘1’ to ‘8’. Herein, since one M/H frame includes 5sub-frames, the total number of data groups within a parade that can beallocated to an M/H frame may correspond to any one multiple of ‘5’ranging from ‘5’ to ‘40’.

FIG. 12 illustrates an example of expanding the assignment process of 3parades, shown in FIG. 11, to 5 sub-frames within an M/H frame.

FIG. 13 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted.

As described above, an M/H frame is divided into 5 sub-frames. Datagroups corresponding to a plurality of parades co-exist in eachsub-frame. Herein, the data groups corresponding to each parade aregrouped by M/H frame units, thereby configuring a single parade.

The data structure shown in FIG. 13 includes 3 parades(parade #0, parade#1, parade #2). Also, a predetermined portion of each data group (i.e.,37 bytes/data group) is used for delivering (or sending) FIC informationassociated with mobile service data, wherein the FIC information isseparately encoded from the RS-encoding process. The FIC region assignedto each data group consists of one FIC segments.

Meanwhile, the concept of an M/H ensemble is applied in the embodimentof the present invention, thereby defining a collection (or group) ofservices. Each M/H ensemble carries the same QoS and is coded with thesame FEC code. Also, each M/H ensemble has the same unique identifier(i.e., ensemble ID) and corresponds to consecutive RS frames.

As shown in FIG. 13, the FIC segment corresponding to each data groupdescribed service information of an M/H ensemble to which thecorresponding data group belongs.

General Description of the Transmitting System

FIG. 14 illustrates a block diagram showing a general structure of adigital broadcast transmitting system according to an embodiment of thepresent invention.

Herein, the digital broadcast transmitting includes a servicemultiplexer 100 and a transmitter 200. Herein, the service multiplexer100 is located in the studio of each broadcast station, and thetransmitter 200 is located in a site placed at a predetermined distancefrom the studio. The transmitter 200 may be located in a plurality ofdifferent locations. Also, for example, the plurality of transmittersmay share the same frequency. And, in this case, the plurality oftransmitters receives the same signal. This corresponds to datatransmission using Single Frequency Network (SFN). Accordingly, in thereceiving system, a channel equalizer may compensate signal distortion,which is caused by a reflected wave, so as to recover the originalsignal. In another example, the plurality of transmitters may havedifferent frequencies with respect to the same channel. This correspondsto data transmission using Multi Frequency Network (MFN).

A variety of methods may be used for data communication each of thetransmitters, which are located in remote positions, and the servicemultiplexer. For example, an interface standard such as a synchronousserial interface for transport of MPEG-2 data (SMPTE-310M). In theSMPTE-310M interface standard, a constant data rate is decided as anoutput data rate of the service multiplexer. For example, in case of the8VSB mode, the output data rate is 19.39 Mbps, and, in case of the 16VSBmode, the output data rate is 38.78 Mbps. Furthermore, in theconventional 8VSB mode transmitting system, a transport stream (TS)packet having a data rate of approximately 19.39 Mbps may be transmittedthrough a single physical channel. Also, in the transmitting systemaccording to the present invention provided with backward compatibilitywith the conventional transmitting system, additional encoding isperformed on the mobile service data. Thereafter, the additionallyencoded mobile service data are multiplexed with the main service datato a TS packet form, which is then transmitted. At this point, the datarate of the multiplexed TS packet is approximately 19.39 Mbps.

At this point, the service multiplexer 100 receives at least one type ofmain service data and table information (e.g., PSI/PSIP table data) foreach main service and encapsulates the received data into a transportstream (TS) packet.

Also, according to an embodiment of the present invention, the servicemultiplexer 100 receives at least one type of mobile service data andtable information (e.g., PSI/PSIP table data) for each mobile serviceand encapsulates the received data into a transport stream (TS) packet.

According to another embodiment of the present invention, the servicemultiplexer 100 receives a RS frame, which is configured of at least onetype of mobile service data and table information for each mobileservice, and encapsulates the received RS frame data into mobile servicedata packets of a transport stream (TS) packet format.

And, the service multiplexer 100 multiplexes the encapsulated TS packetsfor main service and the encapsulated TS packets for mobile servicebased upon a predetermined multiplexing rule, thereby outputting themultiplexed TS packets to the transmitter 200.

At this point, the RS frame has the size of N (row)×187 (column), asshown in FIG. 15. Herein, N represents the length of a row (i.e., numberof columns), and 187 corresponds to the length of a column (i.e., numberof rows.

In the present invention, each row configured of N bytes will bereferred to as an M/H service data packet for simplicity. The M/Hservice data packet may be configured of a 2-byte M/H header and a(N−2)-byte M/H payload. Herein, the assigning 2 bytes to the M/H headerregion is merely exemplary. The above-described configuration may bealtered by the system designer and will, therefore, not be limited onlyto the example presented in the description of the present invention.

The RS frame is generated by collecting (or gathering) table informationand/or mobiles service data collectively corresponding to a size of(N−2) (row)×187(column) bytes.

According to an embodiment of the present invention, the mobile servicedata has the form of an IP datagram. Herein, the RS frame may includetable information and IP datagram corresponding to at least one mobileservice. Also, one RS frame may include table information and IPdatagram corresponding to one or more mobile services. For example, IPdatagram and table information of two different types of mobile servicedata, such as news service (e.g., IP datagram for mobile service 1) andstock information service (e.g., IP datagram for mobile service 2), maybe included in a single RS frame.

More specifically, either table information of a section structure or anIP datagram of a mobile service data may be assigned to an M/H payloadwithin an M/H service data packet configuring the RS frame.Alternatively, either an IP datagram of table information or an IPdatagram of a mobile service data may be assigned to an M/H payloadwithin an M/H service data packet configuring the RS frame.

At this point, the size of the M/H service data packet including the M/Hheader may not be equal to N bytes.

In this case, stuffing bytes may be assigned to the surplus (orremaining) payload region within the corresponding M/H service datapacket. For example, after assigning program table information to an M/Hservice data packet, when the length of the corresponding M/H servicedata packet including the M/H header is equal to (N−20) bytes, stuffingbytes may be assigned to the remaining 20-byte region.

The RS frame may be assigned to at least one of regions A/B/C/D within adata group by the transmitter. In the description of the presentinvention, when the RS frame is assigned to regions A/B/C/D within thedata group, or when the RS frame is assigned to regions A/B, the RSframe will be referred to as a primary RS frame. Alternatively, when theRS frame is assigned to regions C/D, the RS frame will be referred to asa secondary RS frame.

FIG. 16 is a diagram illustrating examples of fields allocated to theM/H header region within the M/H service data packet according to thepresent invention. Examples of the fields include type_indicator field,error_indicator field, stuff_indicator field, and pointer field.

The type_indicator field can allocate 3 bits, for example, andrepresents a type of data allocated to payload within the correspondingM/H service data packet. In other words, the type_indicator fieldindicates whether data of the payload is IP datagram or program tableinformation. At this time, each data type constitutes one logicalchannel. In the logical channel which transmits the IP datagram, severalmobile services are multiplexed and then transmitted. Each mobileservice undergoes demultiplexing in the IP layer.

The error_indicator field can allocate 1 bit, for example, andrepresents whether the corresponding M/H service data packet has anerror. For example, if the error_indicator field has a value of 0, itmeans that there is no error in the corresponding M/H service datapacket. If the error_indicator field has a value of 1, it means thatthere may be an error in the corresponding M/H service data packet.

The stuff_indicator field can allocate 1 bit, for example, andrepresents whether stuffing byte exists in payload of the correspondingM/H service data packet. For example, if the stuff_indicator field has avalue of 0, it means that there is no stuffing byte in the correspondingM/H service data packet. If the stuff_indicator field has a value of 1,it means that stuffing byte exists in the corresponding M/H service datapacket.

The pointer field can allocate 11 bits, for example, and representsposition information where new data (i.e., new signaling information ornew IP datagram) starts in the corresponding M/H service data packet.

For example, if IP datagram for mobile service 1 and IP datagram formobile service 2 are allocated to the first M/H service data packetwithin the RS frame as illustrated in FIG. 15, the pointer field valuerepresents the start position of the IP datagram for mobile service 2within the M/H service data packet.

Also, if there is no new data in the corresponding M/H service datapacket, the corresponding field value is expressed as a maximum valueexemplarily. According to the embodiment of the present invention, since11 bits are allocated to the pointer field, if 2047 is expressed as thepointer field value, it means that there is no new data in the packet.The point where the pointer field value is 0 can be varied depending onthe type_indicator field value and the stuff_indicator field value.

It is to be understood that the order, the position, and the meaning ofthe fields allocated to the header within the M/H service data packetillustrated in FIG. 16 are exemplarily illustrated for understanding ofthe present invention. Since the order, the position and the meaning ofthe fields allocated to the header within the M/H service data packetand the number of additionally allocated fields can easily be modifiedby those skilled in the art, the present invention will not be limitedto the above example.

FIG. 17( a) and FIG. 17( b) illustrate another examples of RS frameaccording to the present invention. FIG. 17( a) illustrates an exampleof primary RS frame to be allocated to regions A/B within the datagroup, and FIG. 17( b) illustrates an example of secondary RS frame tobe allocated to regions C/D within the data group.

In FIG. 17( a) and FIG. 17( b), a column length (i.e., the number ofrows) of the RS frame to be allocated to the regions A/B and a columnlength (i.e., the number of rows) of the RS frame to be allocated to theregions C/D are 187 equally. However, row lengths (i.e, the number ofcolumns) may be different from each other.

According to the embodiment of the present invention, when the rowlength of the primary RS frame to be allocated 7to the regions A/Bwithin the data group is N1 bytes and the row length of the secondary RSframe to be allocated to the regions C/D within the data group is N2bytes, a condition of N1>N2 is satisfied. In this case, N1 and N2 can bevaried depending on the transmission parameter or a region of the datagroup, to which the corresponding RS frame will be transmitted.

For convenience of the description, each row of the N1 and N2 bytes willbe referred to as the M/H service data packet. The M/H service datapacket within the RS frame to be allocated to the regions A/B within thedata group can be comprised of M/H header of 2 bytes and payload of N1−2bytes. Also, the M/H service data packet within the RS frame to beallocated to the regions C/D within the data group can be comprised ofM/H header of 2 bytes and payload of N2−2 bytes.

In the present invention, the primary RS frame for the regions A/Bwithin the data group and the secondary RS frame for the regions C/Dwithin the data group can include at least one of program tableinformation and IP datagram. Also, one RS frame can include IP datagramcorresponding to one or more mobile services.

Corresponding parts of FIG. 15 can be applied to the other parts, whichare not described in FIG. 17( a) and FIG. 17( b).

Meanwhile, the value of N, which corresponds to the number of columnswithin an RS frame, can be decided according to Equation 2.

$\begin{matrix}{N = {\left\lfloor \frac{5 \times {NoG} \times {PL}}{187 + P} \right\rfloor - 2}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

Herein, NoG indicates the number of data groups assigned to a sub-frame.PL represents the number of SCCC payload data bytes assigned to a datagroup. And, P signifies the number of RS parity data bytes added to eachcolumn of the RS frame. Finally, └X┘ is the greatest integer that isequal to or smaller than X.

More specifically, in Equation 2, PL corresponds to the length of an RSframe portion. The value of PL is equivalent to the number of SCCCpayload data bytes that are assigned to the corresponding data group.Herein, the value of PL may vary depending upon the RS frame mode, SCCCblock mode, and SCCC outer code mode. Table 2 to Table 5 belowrespectively show examples of PL values, which vary in accordance withthe RS frame mode, SCCC block mode, and SCCC outer code mode. The SCCCblock mode and the SCCC outer code mode will be described in detail in alater process.

TABLE 2 SCCC outer code mode for Region A for Region B for Region C forRegion D PL 00 00 00 00 9624 00 00 00 01 9372 00 00 01 00 8886 00 00 0101 8634 00 01 00 00 8403 00 01 00 01 8151 00 01 01 00 7665 00 01 01 017413 01 00 00 00 7023 01 00 00 01 6771 01 00 01 00 6285 01 00 01 01 603301 01 00 00 5802 01 01 00 01 5550 01 01 01 00 5064 01 01 01 01 4812Others Reserved

Table 2 shows an example of the PL values for each data group within anRS frame, wherein each PL value varies depending upon the SCCC outercode mode, when the RS frame mode value is equal to ‘00’, and when theSCCC block mode value is equal to ‘00’. For example, when it is assumedthat each SCCC outer code mode value of regions A/B/C/D within the datagroup is equal to ‘00’ (i.e., the block processor 302 of a later blockperforms encoding at a coding rate of 1/2), the PL value within eachdata group of the corresponding RS frame may be equal to 9624 bytes.More specifically, 9624 bytes of mobile service data within one RS framemay be assigned to regions A/B/C/D of the corresponding data group.

TABLE 3 SCCC outer code mode PL 00 9624 01 4812 Others Reserved

Table 3 shows an example of the PL values for each data group within anRS frame, wherein each PL value varies depending upon the SCCC outercode mode, when the RS frame mode value is equal to ‘00’, and when theSCCC block mode value is equal to ‘01’.

TABLE 4 SCCC outer code mode for Region A for Region B PL 00 00 7644 0001 6423 01 00 5043 01 01 3822 Others Reserved

Table 4 shows an example of the PL values for each data group within aprimary RS frame, wherein each PL value varies depending upon the SCCCouter code mode, when the RS frame mode value is equal to ‘01’, and whenthe SCCC block mode value is equal to ‘00’. For example, when each SCCCouter code mode value of regions A/B is equal to ‘00’, 7644 bytes ofmobile service data within a primary RS frame may be assigned to regionsA/B of the corresponding data group.

TABLE 5 SCCC outer code mode for Region C for Region D PL 00 00 1980 0001 1728 01 00 1242 01 01 990 Others Reserved

Table 5 shows an example of the PL values for each data group within asecondary RS frame, wherein each PL value varies depending upon the SCCCouter code mode, when the RS frame mode value is equal to ‘01’, and whenthe SCCC block mode value is equal to ‘00’. For example, when each SCCCouter code mode value of regions C/D is equal to ‘00’, 1980 bytes ofmobile service data within a secondary RS frame may be assigned toregions C/D of the corresponding data group.

Service Multiplexer

FIG. 18 illustrates a block diagram showing an example of the servicemultiplexer. The service multiplexer includes a controller 110 forcontrolling the overall operations of the service multiplexer, a tableinformation generator 120 for the main service, a null packet generator130, an OM packet encapsulator 140, a mobile service multiplexer 150,and a transport multiplexer 160.

The transport multiplexer 160 may include a main service multiplexer 161and a transport stream (TS) packet multiplexer 162.

Referring to FIG. 18, at least one type of compression-encoded mainservice data and table data generated from the table informationgenerator 120 for the main services are inputted to the main servicemultiplexer 161 of the transport multiplexer 160. According to theembodiment of the present invention, the table information generator 120generates PSI/PSIP table data, which is configured in the form of anMPEG-2 private section.

The main service multiplexer 161 respectively encapsulates each of themain service data and the PSI/PSIP table data, which are being inputted,to MPEG-2 TS packet formats, thereby multiplexing the encapsulated TSpackets and outputting the multiplexed packets to the TS packetmultiplexer 162. Herein, the data packet being outputted from the mainservice multiplexer 161 will hereinafter be referred to as a mainservice data packet for simplicity.

The mobile service multiplexer 150 receives and respectivelyencapsulates at least one type of compression-encoded mobile servicedata and the table information (e.g., PSI/PSIP table data) for mobileservices to MPEG-2 TS packet formats. Then, the mobile servicemultiplexer 150 multiplexes the encapsulated TS packets, therebyoutputting the multiplexed packets to the TS packet multiplexer 162.Hereinafter, the data packet being outputted from the mobile servicemultiplexer 150 will be referred to as a mobile service data packet forsimplicity.

Alternatively, the mobile service multiplexer 150 receives andencapsulates an RS frame, which is generated by using at least one typeof compression-encoded mobile service data and the table information formobile services, to MPEG-2 TS packet formats. Then, the mobile servicemultiplexer 150 multiplexes the encapsulated TS packets, therebyoutputting the multiplexed packets to the TS packet multiplexer 162.Hereinafter, the data packet being outputted from the mobile servicemultiplexer 150 will be referred to as a mobile service data packet forsimplicity.

According to an embodiment of the present invention, the mobile servicemultiplexer 150 encapsulates an RS frame, which is inputted in any oneof the formats shown in FIG. 15, FIG. 17A, or FIG. 17B, to a TS packetformat.

At this point, the transmitter 200 requires identification informationin order to identify and process the main service data packet and themobile service data packet. Herein, the identification information mayuse values pre-decided in accordance with an agreement between thetransmitting system and the receiving system, or may be configured of aseparate set of data, or may modify predetermined location value with inthe corresponding data packet.

As an example of the present invention, a different packet identifier(PID) may be assigned to identify each of the main service data packetand the mobile service data packet. More specifically, by assigning aPID, which does not use for the main service data packet, to the mobileservice data packet, the transmitter 200 refers to a PID of data packetinputted, thereby can identify each of the main service data packet andthe mobile service data packet.

In another example, by modifying a synchronization data byte within aheader of the mobile service data, the service data packet may beidentified by using the synchronization data byte value of thecorresponding service data packet. For example, the synchronization byteof the main service data packet directly outputs the value decided bythe ISO/IEC 13818-1 standard (i.e., 0x47) without any modification. Thesynchronization byte of the mobile service data packet modifies andoutputs the value, thereby identifying the main service data packet andthe mobile service data packet. Conversely, the synchronization byte ofthe main service data packet is modified and outputted, whereas thesynchronization byte of the mobile service data packet is directlyoutputted without being modified, thereby enabling the main service datapacket and the mobile service data packet to be identified.

A plurality of methods may be applied in the method of modifying thesynchronization byte. For example, each bit of the synchronization bytemay be inversed, or only a portion of the synchronization byte may beinversed.

As described above, any type of identification information may be usedto identify the main service data packet and the mobile service datapacket. Therefore, the scope of the present invention is not limitedonly to the example set forth in the description of the presentinvention.

Meanwhile, a transport multiplexer used in the conventional digitalbroadcasting system may be used as the transport multiplexer 160according to the present invention. More specifically, in order tomultiplex the mobile service data and the main service data and totransmit the multiplexed data, the data rate of the main service islimited to a data rate of (19.39-K) Mbps. Then, K Mbps, whichcorresponds to the remaining data rate, is assigned as the data rate ofthe mobile service. Thus, the transport multiplexer which is alreadybeing used may be used as it is without any modification.

Herein, the transport multiplexer 160 multiplexes the main service datapacket being outputted from the main service multiplexer 161 and themobile service data packet being outputted from the mobile servicemultiplexer 150. Thereafter, the transport multiplexer 160 transmits themultiplexed data packets to the transmitter 200.

However, in some cases, the output data rate of the mobile servicemultiplexer 150 may not be equal to K Mbps. For example, when theservice multiplexer 100 assigns K Mbps of the 19.39 Mbps to the mobileservice data, and when the remaining (19.39-K) Mbps is, therefore,assigned to the main service data, the data rate of the mobile servicedata that are multiplexed by the service multiplexer 100 actuallybecomes lower than K Mbps. This is because, in case of the mobileservice data, the pre-processor of the transmitting system performsadditional encoding, thereby increasing the amount of data. Eventually,the data rate of the mobile service data, which may be transmitted fromthe service multiplexer 100, becomes smaller than K Mbps.

For example, since the pre-processor of the transmitter performs anencoding process on the mobile service data at a coding rate of at least1/2, the amount of the data outputted from the pre-processor isincreased to more than twice the amount of the data initially inputtedto the pre-processor. Therefore, the sum of the data rate of the mainservice data and the data rate of the mobile service data, both beingmultiplexed by the service multiplexer 100, becomes either equal to orsmaller than 19.39 Mbps.

In order to set the final output data rate of the mobile servicemultiplexer 150 to K Mbps, the service multiplexer 100 of the presentinvention may perform various exemplary operations.

According to an embodiment of the present invention, the null packetgenerator 130 may generate a null data packet, which is then outputtedto the mobile service multiplexer 150. Thereafter, the mobile servicemultiplexer 150 may multiplex the null data packet and the mobileservice data packets, so as to set the output data rate to K Mbps.

At this point, the null data packet is transmitted to the transmitter200, thereby being discarded. More specifically, the null data packet isnot transmitted to the receiving system. In order to do so,identification information for identifying the null data is alsorequired. Herein, the identification information for identifying thenull data may also use a value pre-decided based upon an agreementbetween the transmitting system and the receiving system and may also beconfigured of a separate set of data. And, the identificationinformation for identifying the null data may also change apredetermined position value within the null data packet and use thechanged value. For example, the null packet generator 130 may modify (orchange) a synchronization byte value within the header of the null datapacket, thereby using the changed value as the identificationinformation. Alternatively, the transport_error_indicator flag may beset to ‘1’, thereby being used as the identification information.According to the embodiment of the present invention, thetransport_error_indicator flag within the header of the null data packetis used as the identification information for identifying the null datapacket. In this case, the transport_error_indicator flag of the nulldata packet is set to ‘1’, and the transport_error_indicator flag foreach of the other remaining data packets is reset to ‘0’, so that thenull data packet can be identified (or distinguished).

More specifically, when the null packet generator 130 generated a nulldata packet, and if, among the fields included in the header of the nulldata packet, the transport_error_indicator flag is set to ‘1’ and thentransmitted, the transmitter 200 may identify and discard the null datapacket corresponding to the transport_error_indicator flag.

Herein, any value that can identify the null data packet may be used asthe identification information for identifying the null data packet.Therefore, the present invention will not be limited only to the exampleproposed in the description of the present invention.

As another example of setting (or matching) the final output data rateof the mobile service multiplexer 150 to K Mbps, an operations andmaintenance (OM) packet (also referred to as OMP) may be used. In thiscase, the mobile service multiplexer 150 may multiplex the mobileservice data packet, the null data packet, and the OM packet, so as toset the output data rate to K Mbps.

Meanwhile, signaling data, such as transmission parameters, are requiredfor enabling the transmitter 200 to process the mobile service data.

According to an embodiment of the present invention, the transmissionparameter is inserted in the payload region of the OM packet, therebybeing transmitted to the transmitter.

At this point, in order to enable the transmitter 200 to identify theinsertion of the transmission parameter in the OM packet, identificationinformation that can identify the insertion of the transmissionparameter in the type field of the corresponding OM packet (i.e.,OM_type field).

More specifically, an operations and maintenance packet (OMP) is definedfor the purpose of operating and managing the transmitting system. Forexample, the OMP is configured in an MPEG-2 TS packet format, and thevalue of its respective PID is equal to ‘0x1FFA’. The OMP consists of a4-byte header and a 184-byte payload. Among the 184 bytes, the firstbyte corresponds to the OM_type field indicating the type of thecorresponding OM packet (OMP). And, the remaining 183 bytes correspondto an OM_payload field, wherein actual data are inserted.

According to the present invention, among the reserved field values ofthe OM_type field, a pre-arranged value is used, thereby being capableof indicating that a transmission parameter has been inserted in thecorresponding OM packet. Thereafter, the transmitter 200 may locate (oridentify) the corresponding OMP by referring to the respective PID.Subsequently, by parsing the OM_type field within the OMP, thetransmitter 200 may be able to know (or recognize) whether or not atransmission parameter has been inserted in the corresponding OM packet.

The transmission parameters that can be transmitted to the OM packetinclude M/H frame information (e.g., M/H frame_index), FIC information(e.g., next_FIC_version_number), parade information (e.g.,number_of_parades, parade_id, parade_repetition_cycle, and ensemble_id),group information (e.g., number_of_group and start_group_number), SCCCinformation (e.g., SCCC_block_mode and SCCC_outer_code_mode), RS frameinformation (e.g., RS_Frame_mode and RS_frame_continuity_counter), RSencoding information (e.g., RS_code_mode), and so on.

At this point, the OM packet in which the transmission parameter isinserted may be periodically generated by a constant cycle, so as to bemultiplexed with the mobile service data packet.

The multiplexing rules and the generation of null data packets of themobile service multiplexer 150, the main service multiplexer 161, andthe TS packet multiplexer 160 are controlled by the controller 110.

The TS packet multiplexer 162 multiplexes a data packet being outputtedfrom the main service multiplexer 161 at (19.39-K) Mbps with a datapacket being outputted from the mobile service multiplexer 150 at KMbps. Thereafter, the TS packet multiplexer 162 transmits themultiplexed data packet to the transmitter 200 at a data rate of 19.39Mbps.

Transmitter

FIG. 19 illustrates a block diagram showing an example of thetransmitter 200 according to an embodiment of the present invention.Herein, the transmitter 200 includes a controller 201, a demultiplexer210, a packet jitter mitigator 220, a pre-processor 230, a packetmultiplexer 240, a post-processor 250, a synchronization (sync)multiplexer 260, and a transmission unit 270.

Herein, when a data packet is received from the service multiplexer 100,the demultiplexer 210 should identify whether the received data packetcorresponds to a main service data packet, a mobile service data packet,a null data packet, or an OM packet.

For example, the demultiplexer 210 uses the PID within the received datapacket so as to identify the main service data packet, the mobileservice data packet, and the null data packet. Then, the demultiplexer210 uses a transport_error_indicator field to identify the null datapacket.

If an OM packet is included in the received data packet, the OM packetmay identify using the PID within the received data packet. And by usingthe OM_type field included in the identified OM packet, thedemultiplexer 210 may be able to know whether or not a transmissionparameter is included in the payload region of the corresponding OMpacket and, then, received.

The main service data packet identified by the demultiplexer 210 isoutputted to the packet jitter mitigator 220, the mobile service datapacket is outputted to the pre-processor 230, and the null data packetis discarded. If the transmission parameter is included in the OMpacket, the corresponding transmission parameter is extracted, so as tobe outputted to the corresponding blocks. Thereafter, the OM packet isdiscarded. According to an embodiment of the present invention, thetransmission parameter extracted from the OM packet is outputted to thecorresponding blocks through the controller 201.

The pre-processor 230 performs an additional encoding process of themobile service data included in the service data packet, which isdemultiplexed and outputted from the demultiplexer 210. Thepre-processor 230 also performs a process of configuring a data group sothat the data group may be positioned at a specific place in accordancewith the purpose of the data, which are to be transmitted on atransmission frame. This is to enable the mobile service data to respondswiftly and strongly against noise and channel changes. Thepre-processor 230 may also refer to the transmission parameter extractedin the OM packet when performing the additional encoding process.

Also, the pre-processor 230 groups a plurality of mobile service datapackets to configure a data group. Thereafter, known data, mobileservice data, RS parity data, and MPEG header are allocated topre-determined regions within the data group.

Pre-Processor within Transmitter

FIG. 20 illustrates a block diagram showing the structure of apre-processor 230 according to the present invention. Herein, thepre-processor 230 includes an M/H frame encoder 301, a block processor302, a group formatter 303, a signaling encoder 304, and a packetformatter 305.

The M/H frame encoder 301, which is included in the pre-processor 230having the above-described structure, data-randomizes the mobile servicedata that are inputted to the demultiplexer 210, thereby generating a RSframe corresponding an ensemble. Then, the M/H frame encoder 301performs an encoding process for error correction in RS frame units.

The M/H frame encoder 301 may include at least one RS frame encoder.More specifically, RS frame encoders may be provided in parallel,wherein the number of RS frame encoders is equal to the number ofparades within the M/H frame. As described above, the M/H frame is abasic time cycle period for transmitting at least one parade. Also, eachparade consists of one or two RS frames.

FIG. 21 illustrates a conceptual block diagram of the M/H frame encoder301 according to an embodiment of the present invention. The M/H frameencoder 301 includes an input demultiplexer (DEMUX) 309, M number of RSframe encoders 310 to 31M−1, and an output multiplexer (MUX) 320.Herein, M represent the number of parades included in one M/H frame.

The input demultiplexer 309 output the inputted mobile service datapacket to a corresponding RS frame encoder among M number of RS frameencoders in ensemble units.

At this point, the ensemble may be mapped to the RS frame encoder or aparade. For example, when one parade is configured of one RS frame, eachensemble, RS frame, and parade may be mapped to be in a 1:1:1 (orone-to-one-to-one) correspondence.

According to an embodiment of the present invention, each RS frameencoder groups a plurality of mobile service data packets of theensemble inputted, so as to configure an RS frame corresponding to theensemble and, then, to perform an error correction encoding process inRS frame units. Also, each RS frame encoder divides theerror-correction-encoded RS frame into a plurality of portions, in orderto assign the error-correction-encoded RS frame data to a plurality ofdata groups. Based upon the RS frame mode of Table 1, data within one RSframe may be assigned either to all of regions A/B/C/D within multipledata groups, or to at least one of regions A/B and regions C/D withinmultiple data groups.

When the RS frame mode value is equal to ‘01’, i.e., when the data ofthe primary RS frame are assigned to regions A/B of the correspondingdata group and data of the secondary RS frame are assigned to regionsC/D of the corresponding data group, each RS frame encoder generates aprimary RS frame and a secondary RS frame for each parade. Conversely,when the RS frame mode value is equal to ‘00’, when the data of theprimary RS frame are assigned to all of regions A/B/C/D, each RS frameencoder generates a RS frame (i.e., a primary RS frame) for each parade.

Also, each RS frame encoder divides each RS frame into several portions.Each portion of the RS frame is equivalent to a data amount that can betransmitted by a data group. The output multiplexer (MUX) 320multiplexes portions within M number of RS frame encoders 310 to 310M−1are multiplexed and then outputted to the block processor 302.

For example, if one parade transmits two RS frames, portions of primaryRS frames within M number of RS frame encoders 310 to 310M−1 aremultiplexed and outputted. Thereafter, portions of secondary RS frameswithin M number of RS frame encoders 310 to 310M−1 are multiplexed andtransmitted.

The input demultiplexer (DEMUX) 309 and the output multiplexer (MUX) 320operate based upon the control of the controller 201. The controller 201may provide necessary (or required) FEC modes to each RS frame encoder.The FEC mode includes the RS code mode, which will be described indetail in a later process.

FIG. 22 illustrates a detailed block diagram of an RS frame encoderamong a plurality of RS frame encoders within an M/H frame encoder.

One RS frame encoder may include a primary encoder 410 and a secondaryencoder 420. Herein, the secondary encoder 420 may or may not operatebased upon the RS frame mode. For example, when the RS frame mode valueis equal to ‘00’, as shown in Table 1, the secondary encoder 420 doesnot operate.

The primary encoder 410 may include a data randomizer 411, aReed-Solomon-cyclic redundancy check (RS-CRC) encoder (412), and a RSframe divider 413. And, the secondary encoder 420 may also include adata randomizer 421, a RS-CRC encoder (422), and a RS frame divider 423.

More specifically, the data randomizer 411 of the primary encoder 410receives mobile service data of a primary ensemble outputted from theoutput demultiplexer (DEMUX) 309. Then, after randomizing the receivedmobile service data, the data randomizer 411 outputs the randomized datato the RS-CRC encoder 412. At this point, since the data randomizer 411performs the randomizing process on the mobile service data, therandomizing process that is to be performed by the data randomizer 251of the post-processor 250 on the mobile service data may be omitted. Thedata randomizer 411 may also discard the synchronization byte within themobile service data packet and perform the randomizing process. This isan option that may be chosen by the system designer. In the examplegiven in the present invention, the randomizing process is performedwithout discarding the synchronization byte within the correspondingmobile service data packet.

The RS-CRC encoder 412 generates a RS frame corresponding to therandomized primary ensemble, and performs forward error collection(FEC)-encoding in the RS frame unit using at least one of a Reed-Solomon(RS) code and a cyclic redundancy check (CRC) code. The RS-CRC encoder412 outputs the FEC-encoded RS frame to the RS frame divider 413.

The RS-CRC encoder 412 groups a plurality of mobile service data packetsthat is randomized and inputted, so as to generate a RS frame. Then, theRS-CRC encoder 412 performs at least one of an error correction encodingprocess and an error detection encoding process in RS frame units.Accordingly, robustness may be provided to the mobile service data,thereby scattering group error that may occur during changes in afrequency environment, thereby enabling the mobile service data torespond to the frequency environment, which is extremely vulnerable andliable to frequent changes. Also, the RS-CRC encoder 412 groups aplurality of RS frame so as to generate a super frame, therebyperforming a row permutation process in super frame units. The rowpermutation process may also be referred to as a “row interleavingprocess”. Hereinafter, the process will be referred to as “rowpermutation” for simplicity. In the present invention, the rowpermutation process is optional.

More specifically, when the RS-CRC encoder 412 performs the process ofpermuting each row of the super frame in accordance with apre-determined rule, the position of the rows within the super framebefore and after the row permutation process is changed. If the rowpermutation process is performed by super frame units, and even thoughthe section having a plurality of errors occurring therein becomes verylong, and even though the number of errors included in the RS frame,which is to be decoded, exceeds the extent of being able to becorrected, the errors become dispersed within the entire super frame.Thus, the decoding ability is even more enhanced as compared to a singleRS frame.

At this point, as an example of the present invention, RS-encoding isapplied for the error correction encoding process, and a cyclicredundancy check (CRC) encoding is applied for the error detectionprocess in the RS-CRC encoder 412. When performing the RS-encoding,parity data that are used for the error correction are generated. And,when performing the CRC encoding, CRC data that are used for the errordetection are generated. The CRC data generated by CRC encoding may beused for indicating whether or not the mobile service data have beendamaged by the errors while being transmitted through the channel. Inthe present invention, a variety of error detection coding methods otherthan the CRC encoding method may be used, or the error correction codingmethod may be used to enhance the overall error correction ability ofthe receiving system.

Herein, the RS-CRC encoder 412 refers to a pre-determined transmissionparameter provided by the controller 201 so as to perform operationsincluding RS frame configuration, RS encoding, CRC encoding, super frameconfiguration, and row permutation in super frame units.

FIG. 23( a) and FIG. 23( b) illustrate a process of one or two RS framebeing divided into several portions, based upon an RS frame mode value,and a process of each portion being assigned to a corresponding regionwithin the respective data group. According to an embodiment of thepresent invention, the data assignment within the data group isperformed by the group formatter 303.

More specifically, FIG. 23( a) shows an example of the RS frame modevalue being equal to ‘00’. Herein, only the primary encoder 410 of FIG.22 operates, thereby forming one RS frame for one parade. Then, the RSframe is divided into several portions, and the data of each portion areassigned to regions A/B/C/D within the respective data group. FIG. 23(b) shows an example of the RS frame mode value being equal to ‘01’.Herein, both the primary encoder 410 and the secondary encoder 420 ofFIG. 22 operate, thereby forming two RS frames for one parade, i.e., oneprimary RS frame and one secondary RS frame. Then, the primary RS frameis divided into several portions, and the secondary RS frame is dividedinto several portions. At this point, the data of each portion of theprimary RS frame are assigned to regions A/B within the respective datagroup. And, the data of each portion of the secondary RS frame areassigned to regions C/D within the respective data group.

Detailed Description of the RS Frame

FIG. 24( a) illustrates an example of an RS frame being generated fromthe RS-CRC encoder 412 according to the present invention.

When the RS frame is generated, as shown in FIG. 24( a), the RS-CRCencoder 412 performs a (Nc,Kc)-RS encoding process on each column, so asto generate Nc-Kc(=P) number of parity bytes. Then, the RS-CRC encoder412 adds the newly generated P number of parity bytes after the verylast byte of the corresponding column, thereby generating a column of(187+P) bytes. Herein, as shown in FIG. 24( a), Kc is equal to 187(i.e., Kc=187), and Nc is equal to 187+P (i.e., Nc=187+P). Herein, thevalue of P may vary depending upon the RS code mode. Table 6 below showsan example of an RS code mode, as one of the RS encoding information.

TABLE 6 RS code mode RS code Number of Parity Bytes (P) 00 (211, 187) 2401 (223, 187) 36 10 (235, 187) 48 11 Reserved Reserved

Table 6 shows an example of 2 bits being assigned in order to indicatethe RS code mode. The RS code mode represents the number of parity bytescorresponding to the RS frame.

For example, when the RS code mode value is equal to ‘10’,(235,187)-RS-encoding is performed on the RS frame of FIG. 24( a), so asto generate 48 parity data bytes. Thereafter, the 48 parity bytes areadded after the last data byte of the corresponding column, therebygenerating a column of 235 data bytes.

When the RS frame mode value is equal to ‘00’ in Table 1 (i.e., when theRS frame mode indicates a single RS frame), only the RS code mode of thecorresponding RS frame is indicated. However, when the RS frame modevalue is equal to ‘01’ in Table 1 (i.e., when the RS frame modeindicates multiple RS frames), the RS code mode corresponding to aprimary RS frame and a secondary RS frame. More specifically, it ispreferable that the RS code mode is independently applied to the primaryRS frame and the secondary RS frame.

When such RS encoding process is performed on all N number of columns, aRS frame having the size of N(row)×(187+P) (column) bytes may begenerated, as shown in FIG. 24( b).

Each row of the RS frame is configured of N bytes. However, dependingupon channel conditions between the transmitting system and thereceiving system, error may be included in the RS frame. When errorsoccur as described above, CRC data (or CRC code or CRC checksum) may beused on each row unit in order to verify whether error exists in eachrow unit.

The RS-CRC encoder 412 may perform CRC encoding on the mobile servicedata being RS encoded so as to create (or generate) the CRC data. TheCRC data being generated by CRC encoding may be used to indicate whetherthe mobile service data have been damaged while being transmittedthrough the channel.

The present invention may also use different error detection encodingmethods other than the CRC encoding method. Alternatively, the presentinvention may use the error correction encoding method to enhance theoverall error correction ability of the receiving system.

FIG. 24( c) illustrates an example of using a 2-byte (i.e., 16-bit) CRCchecksum as the CRC data. Herein, a 2-byte CRC checksum is generated forN number of bytes of each row, thereby adding the 2-byte CRC checksum atthe end of the N number of bytes. Thus, each row is expanded to (N+2)number of bytes. Equation 3 below corresponds to an exemplary equationfor generating a 2-byte CRC checksum for each row being configured of Nnumber of bytes.g(x)=x ¹⁶ +x ¹² +x ⁵⁺¹  Equation 3

The process of adding a 2-byte checksum in each row is only exemplary.Therefore, the present invention is not limited only to the exampleproposed in the description set forth herein. As described above, whenthe process of RS encoding and CRC encoding are completed, the(Nx187)-byte RS frame is expanded to a (N+2)×(187+P)-byte RS frame.Based upon an error correction scenario of a RS frame expanded asdescribed above, the data bytes within the RS frame are transmittedthrough a channel in a row direction. At this point, when a large numberof errors occur during a limited period of transmission time, errorsalso occur in a row direction within the RS frame being processed with adecoding process in the receiving system. However, in the perspective ofRS encoding performed in a column direction, the errors are shown asbeing scattered. Therefore, error correction may be performed moreeffectively. At this point, a method of increasing the number of paritydata bytes (P) may be used in order to perform a more intense errorcorrection process. However, using this method may lead to a decrease intransmission efficiency. Therefore, a mutually advantageous method isrequired. Furthermore, when performing the decoding process, an erasuredecoding process may be used to enhance the error correctionperformance.

Additionally, the RS-CRC encoder 412 according to the present inventionalso performs a row permutation (or interleaving) process in super frameunits in order to further enhance the error correction performance whenerror correction the RS frame.

FIG. 25( a) to FIG. 25( d) illustrates an example of performing a rowpermutation process in super frame units according to the presentinvention. More specifically, G number of RS frames RS-CRC-encoded isgrouped to form a super frame, as shown in FIG. 25( a). At this point,since each RS frame is formed of (N+2)×(187+P) number of bytes, onesuper frame is configured to have the size of (N+2)×(187+P)×G bytes.

When a row permutation process permuting each row of the super frameconfigured as described above is performed based upon a pre-determinedpermutation rule, the positions of the rows prior to and after beingpermuted (or interleaved) within the super frame may be altered. Morespecifically, the i^(th) row of the super frame prior to theinterleaving process, as shown in FIG. 25( b), is positioned in thej^(th) row of the same super frame after the row permutation process, asshown in FIG. 25( c). The above-described relation between i and j canbe easily understood with reference to a permutation rule as shown inEquation 4 below.j=G(i mod (187+P))+└i/(187+P)┘i=(187+P)(j mod G)+└j/G┘  Equation 4

where 0≦i, j≦(187+P)G−1; or

where 0≦i, j<(187+P)G

Herein, each row of the super frame is configured of (N+2) number ofdata bytes even after being row-permuted in super frame units.

When all row permutation processes in super frame units are completed,the super frame is once again divided into G number of row-permuted RSframes, as shown in FIG. 25( d), and then provided to the RS framedivider 413. Herein, the number of RS parity bytes and the number ofcolumns should be equally provided in each of the RS frames, whichconfigure a super frame. As described in the error correction scenarioof a RS frame, in case of the super frame, a section having a largenumber of error occurring therein is so long that, even when one RSframe that is to be decoded includes an excessive number of errors(i.e., to an extent that the errors cannot be corrected), such errorsare scattered throughout the entire super frame. Therefore, incomparison with a single RS frame, the decoding performance of the superframe is more enhanced.

The above description of the present invention corresponds to theprocesses of forming (or creating) and encoding an RS frame, when a datagroup is divided into regions A/B/C/D, and when data of an RS frame areassigned to all of regions A/B/C/D within the corresponding data group.More specifically, the above description corresponds to an embodiment ofthe present invention, wherein one RS frame is transmitted using oneparade. In this embodiment, the secondary encoder 420 does not operate(or is not active).

Meanwhile, 2 RS frames are transmitting using one parade, the data ofthe primary RS frame may be assigned to regions A/B within the datagroup and be transmitted, and the data of the secondary RS frame may beassigned to regions C/D within the data group and be transmitted. Atthis point, the primary encoder 410 receives the mobile service datapackets that are to be assigned to regions A/B within the data group, soas to form the primary RS frame, thereby performing RS-encoding andCRC-encoding. Similarly, the secondary encoder 420 receives the mobileservice data packets that are to be assigned to regions C/D within thedata group, so as to form the secondary RS frame, thereby performingRS-encoding and CRC-encoding. More specifically, the primary RS frameand the secondary RS frame are generated independently.

FIG. 26 illustrates examples of receiving the mobile service datapackets that are to be assigned to regions A/B within the data group, soas to form the primary RS frame, and receives the mobile service datapackets that are to be assigned to regions C/D within the data group, soas to form the secondary RS frame, thereby performing error correctionencoding and error detection encoding on each of the first and secondaryRS frames.

More specifically, FIG. 26( a) illustrates an example of the RS-CRCencoder 412 of the primary encoder 410 receiving mobile service datapackets of the primary ensemble that are to be assigned to regions A/Bwithin the corresponding data group, so as to generated an RS framehaving the size of N1(row)×187(column). Then, in this example, theprimary encoder 410 performs RS-encoding on each column of the RS framegenerated as described above, thereby adding P1 number of parity databytes in each column. Finally, the primary encoder 410 performsCRC-encoding on each row, thereby adding a 2-byte checksum in each row.

FIG. 26( b) illustrates an example of the RS-CRC encoder 422 of thesecondary encoder 420 receiving mobile service data packets of thesecondary ensemble that are to be assigned to regions C/D within thecorresponding data group, so as to generate an RS frame having the sizeof N2(row)×187(column). Then, in this example, the secondary encoder 420performs RS-encoding on each column of the RS frame generated asdescribed above, thereby adding P2 number of parity data bytes in eachcolumn. Finally, the secondary encoder 420 performs CRC-encoding on eachrow, thereby adding a 2-byte checksum in each row.

At this point, each of the RS-CRC encoders 412 and 422 may refer to apre-determined transmission parameter provided by the controller 201,the RS-CRC encoders 412 and 422 may be informed of M/H frameinformation, FIC information, RS frame information (including RS framemode information), RS encoding information (including RS code mode),SCCC information (including SCCC block mode information and SCCC outercode mode information), data group information, and region informationwithin a data group. The RS-CRC encoders 412 and 422 may refer to thetransmission parameters for the purpose of RS frame configuration, errorcorrection encoding, error detection encoding. Furthermore, thetransmission parameters should also be transmitted to the receivingsystem so that the receiving system can perform a normal decodingprocess. At this point, as an example of the present invention, thetransmission parameter is transmitted through transmission parameterchannel (TPC) to a receiving system. The TPC will be described in detailin a later.

The data of the primary RS frame, which is encoded by RS frame units androw-permuted by super frame units from the RS-CRC encoder 412 of theprimary encoder 410, are outputted to the RS frame divider 413. If thesecondary encoder 420 also operates in the embodiment of the presentinvention, the data of the secondary RS frame, which is encoded by RSframe units and row-permuted by super frame units from the RS-CRCencoder 422 of the secondary encoder 420, are outputted to the RS framedivider 423. The RS frame divider 413 of the primary encoder 410 dividesthe primary RS frame into several portions, which are then outputted tothe output multiplexer (MUX) 320. Each portion of the primary RS frameis equivalent to a data amount that can be transmitted by one datagroup. Similarly, the RS frame divider 423 of the secondary encoder 420divides the secondary RS frame into several portions, which are thenoutputted to the output multiplexer (MUX) 320.

Hereinafter, the RS frame divider 413 of the primary RS encoder 410 willnow be described in detail. Also, in order to simplify the descriptionof the present invention, it is assumed that an RS frame having the sizeof N(row)×187(column), as shown in FIG. 24( a) to FIG. 24( c), that Pnumber of parity data bytes are added to each column by RS-encoding theRS frame, and that a 2-byte checksum is added to each row byCRC-encoding the RS frame. Accordingly, the RS frame divider 413 divides(or partitions) the encoded RS frame having the size of(N+2)(row)×187(column) into several portions, each having the size of PL(wherein PL corresponds to the length of the RS frame portion).

At this point, as shown in Table 2 to Table 5, the value of PL may varydepending upon the RS frame mode, SCCC block mode, and SCCC outer codermode. Also, the total number of data bytes of the RS-encoded andCRC-encoded RS frame is equal to or smaller than 5×NoG×PL. In this case,the RS frame is divided (or partitioned) into ((5×NoG)−1) number ofportions each having the size of PL and one portion having a size equalto smaller than PL. More specifically, with the exception of the lastportion of the RS frame, each of the remaining portions of the RS framehas an equal size of PL. If the size of the last portion is smaller thanPL, a stuffing byte (or dummy byte) may be inserted in order to fill (orreplace) the lacking number of data bytes, thereby enabling the lastportion of the RS frame to also be equal to PL. Each portion of an RSframe corresponds to the amount of data that are to be SCCC-encoded andmapped into a single data group of a parade.

FIG. 27( a) and FIG. 27( b) respectively illustrate examples of adding Snumber of stuffing bytes, when an RS frame having the size of(N+2)(row)×(187+P) (column) is divided into 5×NoG number of portions,each having the size of PL. More specifically, the RS-encoded andCRC-encoded RS frame, shown in FIG. 27( a), is divided into severalportions, as shown in FIG. 27( b). The number of divided portions at theRS frame is equal to (5×NoG). Particularly, the first ((5×NoG)−1) numberof portions each has the size of PL, and the last portion of the RSframe may be equal to or smaller than PL. If the size of the lastportion is smaller than PL, a stuffing byte (or dummy byte) may beinserted in order to fill (or replace) the lacking number of data bytes,as shown in Equation 5 below, thereby enabling the last portion of theRS frame to also be equal to PL.S=(5×NoG×PL)−((N+2)×(187+P))  Equation 5

Herein, each portion including data having the size of PL passes throughthe output multiplexer 320 of the M/H frame encoder 301, which is thenoutputted to the block processor 302.

At this point, the mapping order of the RS frame portions to a parade ofdata groups in not identical with the group assignment order defined inEquation 1. When given the group positions of a parade in an M/H frame,the SCCC-encoded RS frame portions will be mapped in a time order (i.e.,in a left-to-right direction).

For example, as shown in FIG. 11, data groups of the 2^(nd) parade(Parade #1) are first assigned (or allocated) to the 13^(th) slot (Slot#12) and then assigned to the 3^(rd) slot (Slot #2). However, when thedata are actually placed in the assigned slots, the data are placed in atime sequence (or time order, i.e., in a left-to-right direction). Morespecifically, the 1^(st) data group of Parade #1 is placed in Slot #2,and the 2^(nd) data group of Parade #1 is placed in Slot #12.

Block Processor

Meanwhile, the block processor 302 performs an SCCC outer encodingprocess on the output of the M/H frame encoder 301. More specifically,the block processor 302 receives the data of each error correctionencoded portion. Then, the block processor 302 encodes the data onceagain at a coding rate of 1/H (wherein H is an integer equal to orgreater than 2 (i.e., H≧2)), thereby outputting the 1/H-rate encodeddata to the group formatter 303. According to the embodiment of thepresent invention, the input data are encoded either at a coding rate of1/2 (also referred to as “1/2-rate encoding”) or at a coding rate of 1/4(also referred to as “1/4-rate encoding”). The data of each portionoutputted from the M/H frame encoder 301 may include at least one ofpure mobile service data, RS parity data, CRC data, and stuffing data.However, in a broader meaning, the data included in each portion maycorrespond to data for mobile services. Therefore, the data included ineach portion will all be considered as mobile service data and describedaccordingly.

The group formatter 303 inserts the mobile service dataSCCC-outer-encoded and outputted from the block processor 302 in thecorresponding region within the data group, which is formed inaccordance with a pre-defined rule. Also, in association with the datadeinterleaving process, the group formatter 303 inserts various placeholders (or known data place holders) in the corresponding region withinthe data group. Thereafter, the group formatter 303 deinterleaves thedata within the data group and the place holders.

According to the present invention, with reference to data after beingdata-interleaved, as shown in FIG. 5, a data groups is configured of 10M/H blocks (B1 to B10) and divided into 4 regions (A, B, C, and D).Also, as shown in FIG. 5, when it is assumed that the data group isdivided into a plurality of hierarchical regions, as described above,the block processor 302 may encode the mobile service data, which are tobe inserted to each region based upon the characteristic of eachhierarchical region, at different coding rates. For example, the blockprocessor 302 may encode the mobile service data, which are to beinserted in region A/B within the corresponding data group, at a codingrate of 1/2. Then, the group formatter 303 may insert the 1/2-rateencoded mobile service data to region A/B. Also, the block processor 302may encode the mobile service data, which are to be inserted in regionC/D within the corresponding data group, at a coding rate of 1/4 havinghigher (or stronger) error correction ability than the 1/2-coding rate.Thereafter, the group formatter 303 may insert the 1/2-rate encodedmobile service data to region C/D. In another example, the blockprocessor 302 may encode the mobile service data, which are to beinserted in region C/D, at a coding rate having higher error correctionability than the 1/4-coding rate. Then, the group formatter 303 mayeither insert the encoded mobile service data to region C/D, asdescribed above, or leave the data in a reserved region for futureusage.

According to another embodiment of the present invention, the blockprocessor 302 may perform a 1/H-rate encoding process in SCCC blockunits. Herein, the SCCC block includes at least one M/H block. At thispoint, when 1/H-rate encoding is performed in M/H block units, the M/Hblocks (B1 to B10) and the SCCC block (SCB1 to SCB10) become identicalto one another (i.e., SCB1=B1, SCB2=B2, SCB3=B3, SCB4=B4, SCB5=B5,SCB6=B6, SCB7=B7, SCB8=B8, SCB9=B9, and SCB10=B10). For example, the M/Hblock 1 (B1) may be encoded at the coding rate of 1/2, the M/H block 2(B2) may be encoded at the coding rate of 1/4, and the M/H block 3 (B3)may be encoded at the coding rate of 1/2. The coding rates are appliedrespectively to the remaining M/H blocks.

Alternatively, a plurality of M/H blocks within regions A, B, C, and Dmay be grouped into one SCCC block, thereby being encoded at a codingrate of 1/H in SCCC block units. Accordingly, the receiving performanceof region C/D may be enhanced. For example, M/H block 1 (B1) to M/Hblock 5 (B5) may be grouped into one SCCC block and then encoded at acoding rate of 1/2. Thereafter, the group formatter 303 may insert the1/2-rate encoded mobile service data to a section starting from M/Hblock 1 (B1) to M/H block 5 (B5). Furthermore, M/H block 6 (B6) to M/Hblock 10 (B10) may be grouped into one SCCC block and then encoded at acoding rate of 1/4. Thereafter, the group formatter 303 may insert the1/4-rate encoded mobile service data to another section starting fromM/H block 6 (B6) to M/H block 10 (B10). In this case, one data group mayconsist of two SCCC blocks.

According to another embodiment of the present invention, one SCCC blockmay be formed by grouping two M/H blocks. For example, M/H block 1 (B1)and M/H block 6 (B6) may be grouped into one SCCC block (SCB1).Similarly, M/H block 2 (B2) and M/H block 7 (B7) may be grouped intoanother SCCC block (SCB2). Also, M/H block 3 (B3) and M/H block 8 (B8)may be grouped into another SCCC block (SCB3). And, M/H block 4 (B4) andM/H block 9 (B9) may be grouped into another SCCC block (SCB4).Furthermore, M/H block 5 (B5) and M/H block 10 (B10) may be grouped intoanother SCCC block (SCB5). In the above-described example, the datagroup may consist of 10 M/H blocks and 5 SCCC blocks. Accordingly, in adata (or signal) receiving environment undergoing frequent and severechannel changes, the receiving performance of regions C and D, which isrelatively more deteriorated than the receiving performance of region A,may be reinforced. Furthermore, since the number of mobile service datasymbols increases more and more from region A to region D, the errorcorrection encoding performance becomes more and more deteriorated.Therefore, when grouping a plurality of M/H block to form one SCCCblock, such deterioration in the error correction encoding performancemay be reduced.

As described-above, when the block processor 302 performs encoding at a1/H-coding rate, information associated with SCCC should be transmittedto the receiving system in order to accurately recover the mobileservice data. Table 7 below shows an example of a SCCC block mode, whichindicating the relation between an M/H block and an SCCC block, amongdiverse SCCC block information.

TABLE 7 SCCC Block Mode 00 01 10 11 Description One M/H Block Two M/HBlocks per SCCC Block per SCCC Block Reserved Reserved SCB SCB input,SCB input, M/H Block M/H Blocks SCB1 B1 B1 + B6 SCB2 B2 B2 + B7 SCB3 B3B3 + B8 SCB4 B4 B4 + B9 SCB5 B5 B5 + B10 SCB6 B6 — SCB7 B7 — SCB8 B8 —SCB9 B9 — SCB10 B10 —

More specifically, Table 4 shows an example of 2 bits being allocated inorder to indicate the SCCC block mode. For example, when the SCCC blockmode value is equal to ‘00’, this indicates that the SCCC block and theM/H block are identical to one another. Also, when the SCCC block modevalue is equal to ‘01’, this indicates that each SCCC block isconfigured of 2 M/H blocks.

As described above, if one data group is configured of 2 SCCC blocks,although it is not indicated in Table 7, this information may also beindicated as the SCCC block mode. For example, when the SCCC block modevalue is equal to ‘10’, this indicates that each SCCC block isconfigured of 5 M/H blocks and that one data group is configured of 2SCCC blocks. Herein, the number of M/H blocks included in an SCCC blockand the position of each M/H block may vary depending upon the settingsmade by the system designer. Therefore, the present invention will notbe limited to the examples given herein. Accordingly, the SCCC modeinformation may also be expanded.

An example of a coding rate information of the SCCC block, i.e., SCCCouter code mode, is shown in Table 8 below.

TABLE 8 SCCC outer code mode (2 bits) Description 00 Outer code rate ofSCCC block is 1/2 rate 01 Outer code rate of SCCC block is 1/4 rate 10Reserved 11 Reserved

More specifically, Table 8 shows an example of 2 bits being allocated inorder to indicate the coding rate information of the SCCC block. Forexample, when the SCCC outer code mode value is equal to ‘00’, thisindicates that the coding rate of the corresponding SCCC block is 1/2.And, when the SCCC outer code mode value is equal to ‘01’, thisindicates that the coding rate of the corresponding SCCC block is 1/4.

If the SCCC block mode value of Table 7 indicates ‘00’, the SCCC outercode mode may indicate the coding rate of each M/H block with respect toeach M/H block. In this case, since it is assumed that one data groupincludes 10 M/H blocks and that 2 bits are allocated for each SCCC blockmode, a total of 20 bits are required for indicating the SCCC blockmodes of the 10 M/H modes. In another example, when the SCCC block modevalue of Table 7 indicates ‘00’, the SCCC outer code mode may indicatethe coding rate of each region with respect to each region within thedata group. In this case, since it is assumed that one data groupincludes 4 regions (i.e., regions A, B, C, and D) and that 2 bits areallocated for each SCCC block mode, a total of 8 bits are required forindicating the SCCC block modes of the 4 regions. In another example,when the SCCC block mode value of Table 7 is equal to ‘01’, each of theregions A, B, C, and D within the data group has the same SCCC outercode mode.

Meanwhile, an example of an SCCC output block length (SOBL) for eachSCCC block, when the SCCC block mode value is equal to ‘00’, is shown inTable 9 below.

TABLE 9 SIBL SCCC Block SOBL 1/2 rate 1/4 rate SCB1 (B1) 528 264 132SCB2 (B2) 1536 768 384 SCB3 (B3) 2376 1188 594 SCB4 (B4) 2388 1194 597SCB5 (B5) 2772 1386 693 SCB6 (B6) 2472 1236 618 SCB7 (B7) 2772 1386 693SCB8 (B8) 2508 1254 627 SCB9 (B9) 1416 708 354 SCB10 (B10) 480 240 120

More specifically, when given the SCCC output block length (SOBL) foreach SCCC block, an SCCC input block length (SIBL) for eachcorresponding SCCC block may be decided based upon the outer coding rateof each SCCC block. The SOBL is equivalent to the number of SCCC output(or outer-encoded) bytes for each SCCC block. And, the SIBL isequivalent to the number of SCCC input (or payload) bytes for each SCCCblock. Table 10 below shows an example of the SOBL and SIBL for eachSCCC block, when the SCCC block mode value is equal to ‘01’.

TABLE 10 SIBL SCCC Block SOBL 1/2 rate 1/4 rate SCB1 (B1 + B6) 528 264132 SCB2 (B2 + B7) 1536 768 384 SCB3 (B3 + B8) 2376 1188 594 SCB4 (B4 +B9) 2388 1194 597 SCB5 (B5 + B10) 2772 1386 693

In order to do so, as shown in FIG. 28, the block processor 302 includesa RS frame portion-SCCC block converter 511, a byte-bit converter 512, aconvolution encoder 513, a symbol interleaver 514, a symbol-byteconverter 515, and an SCCC block-M/H block converter 516. Theconvolutional encoder 513 and the symbol interleaver 514 are virtuallyconcatenated with the trellis encoding module in the post-processor inorder to configure an SCCC block. More specifically, the RS frameportion-SCCC block converter 511 divides the RS frame portions, whichare being inputted, into multiple SCCC blocks using the SIBL of Table 9and Table 10 based upon the RS code mode, SCCC block mode, and SCCCouter code mode. Herein, the M/H frame encoder 301 may output onlyprimary RS frame portions or both primary RS frame portions andsecondary RS frame portions in accordance with the RS frame mode.

When the RS Frame mode is set to ‘00’, a portion of the primary RS Frameequal to the amount of data, which are to be SCCC outer encoded andmapped to 10 M/H blocks (B1 to B10) of a data group, will be provided tothe block processor 302. When the SCCC block mode value is equal to‘00’, then the primary RS frame portion will be split into 10 SCCCBlocks according to Table 9. Alternatively, when the SCCC block modevalue is equal to ‘01’, then the primary RS frame will be split into 5SCCC blocks according to Table 10.

When the RS frame mode value is equal to ‘01’, then the block processor302 may receive two RS frame portions. The RS frame mode value of ‘01’will not be used with the SCCC block mode value of ‘01’. The firstportion from the primary RS frame will be SCCC-outer-encoded as SCCCBlocks SCB3, SCB4, SCB5, SCB6, SCB7, and SCB8 by the block processor302. The SCCC Blocks SCB3 and SCB8 will be mapped to region B and theSCCC blocks SCB4, SCB5, SCB6, and SCB7 shall be mapped to region A bythe group formatter 303. The second portion from the secondary RS framewill also be SCCC-outer-encoded, as SCB1, SCB2, SCB9, and SCB10, by theblock processor 302. The group formatter 303 will map the SCCC blocksSCB1 and SCB10 to region D as the M/H blocks B1 and B10, respectively.Similarly, the SCCC blocks SCB2 and SCB9 will be mapped to region C asthe M/H blocks B2 and B9.

The byte-bit converter 512 identifies the mobile service data bytes ofeach SCCC block outputted from the RS frame portion-SCCC block converter511 as data bits, which are then outputted to the convolution encoder513. The convolution encoder 513 performs one of 1/2-rate encoding and1/4-rate encoding on the inputted mobile service data bits.

FIG. 29 illustrates a detailed block diagram of the convolution encoder513. The convolution encoder 513 includes two delay units 521 and 523and three adders 522, 524, and 525. Herein, the convolution encoder 513encodes an input data bit U and outputs the coded bit U to 5 bits (u0 tou4). At this point, the input data bit U is directly outputted asuppermost bit u0 and simultaneously encoded as lower bit u1u2u3u4 andthen outputted. More specifically, the input data bit U is directlyoutputted as the uppermost bit u0 and simultaneously outputted to thefirst and third adders 522 and 525.

The first adder 522 adds the input data bit U and the output bit of thefirst delay unit 521 and, then, outputs the added bit to the seconddelay unit 523. Then, the data bit delayed by a pre-determined time(e.g., by 1 clock) in the second delay unit 523 is outputted as a lowerbit u1 and simultaneously fed-back to the first delay unit 521. Thefirst delay unit 521 delays the data bit fed-back from the second delayunit 523 by a pre-determined time (e.g., by 1 clock). Then, the firstdelay unit 521 outputs the delayed data bit as a lower bit u2 and, atthe same time, outputs the fed-back data to the first adder 522 and thesecond adder 524. The second adder 524 adds the data bits outputted fromthe first and second delay units 521 and 523 and outputs the added databits as a lower bit u3. The third adder 525 adds the input data bit Uand the output of the second delay unit 523 and outputs the added databit as a lower bit u4.

At this point, the first and second delay units 521 and 523 are reset to‘0’, at the starting point of each SCCC block. The convolution encoder513 of FIG. 29 may be used as a 1/2-rate encoder or a 1/4-rate encoder.More specifically, when a portion of the output bit of the convolutionencoder 513, shown in FIG. 29, is selected and outputted, theconvolution encoder 513 may be used as one of a 1/2-rate encoder and a1/4-rate encoder. Table 11 below shown an example of output symbols ofthe convolution encoder 513.

TABLE 11 1/4 rate Region 1/2 rate SCCC block mode = ‘00’ SCCC block mode= ‘01’ A, B (u0, u1) (u0, u2), (u1, u3) (u0, u2), (u1, u4) C, D (u0,u1), (u3, u4)

For example, at the 1/2-coding rate, 1 output symbol (i.e., u0 and u1bits) may be selected and outputted. And, at the 1/4-coding rate,depending upon the SCCC block mode, 2 output symbols (i.e., 4 bits) maybe selected and outputted. For example, when the SCCC block mode valueis equal to ‘01’, and when an output symbol configured of u0 and u2 andanother output symbol configured of u1 and u4 are selected andoutputted, a 1/4-rate coding result may be obtained.

The mobile service data encoded at the coding rate of 1/2 or 1/4 by theconvolution encoder 513 are outputted to the symbol interleaver 514. Thesymbol interleaver 514 performs block interleaving, in symbol units, onthe output data symbol of the convolution encoder 513. Morespecifically, the symbol interleaver 514 is a type of block interleaver.Any interleaver performing structural rearrangement (or realignment) maybe applied as the symbol interleaver 514 of the block processor.However, in the present invention, a variable length symbol interleaverthat can be applied even when a plurality of lengths is provided for thesymbol, so that its order may be rearranged, may also be used.

FIG. 30 illustrates a symbol interleaver according to an embodiment ofthe present invention. Particularly, FIG. 30 illustrates an example ofthe symbol interleaver when B=2112 and L=4096. Herein, B indicates ablock length in symbols that are outputted for symbol interleaving fromthe convolution encoder 513. And, L represents a block length in symbolsthat are actually interleaved by the symbol interleaver 514. At thispoint, the block length in symbols B inputted to the symbol interleaver514 is equivalent to 4×SOBL. More specifically, since one symbol isconfigured of 2 bits, the value of B may be set to be equal to 4×SOBL.

In the present invention, when performing the symbol-intereleavingprocess, the conditions of L=2^(m) (wherein m is an integer) and of L≧Bshould be satisfied. If there is a difference in value between B and L,(L−B) number of null (or dummy) symbols is added, thereby generating aninterleaving pattern, as shown in P′(i) of FIG. 30. Therefore, B becomesa block size of the actual symbols that are inputted to the symbolinterleaver 514 in order to be interleaved. L becomes an interleavingunit when the interleaving process is performed by an interleavingpattern generated from the symbol interleaver 514.

Equation 6 shown below describes the process of sequentially receiving Bnumber of symbols, the order of which is to be rearranged, and obtainingan L value satisfying the conditions of L=2^(m) (wherein m is aninteger) and of L≧B, thereby generating the interleaving so as torealign (or rearrange) the symbol order.

In relation to all places, wherein 0≦i≦B−1,P′(i)={89×i×(i+1)/2} mod L  Equation 6

Herein, L≧B, L=2^(m), wherein m is an integer.

As shown in P′(i) of FIG. 30, the order of B number of input symbols and(L−B) number of null symbols is rearranged by using the above-mentionedEquation 6. Then, as shown in P(i) of FIG. 30, the null byte places areremoved, so as to rearrange the order. Starting with the lowest value ofi, the P(i) are shifted to the left in order to fill the empty entrylocations. Thereafter, the symbols of the aligned interleaving patternP(i) are outputted to the symbol-byte converter 515 in order. Herein,the symbol-byte converter 515 converts to bytes the mobile service datasymbols, having the rearranging of the symbol order completed and thenoutputted in accordance with the rearranged order, and thereafteroutputs the converted bytes to the SCCC block-M/H block converter 516.The SCCC block-M/H block converter 516 converts the symbol-interleavedSCCC blocks to M/H blocks, which are then outputted to the groupformatter 303.

If the SCCC block mode value is equal to ‘00’, the SCCC block is mappedat a one-to-one (1:1) correspondence with each M/H block within the datagroup. In another example, if the SCCC block mode value is equal to‘01’, each SCCC block is mapped with two M/H blocks within the datagroup. For example, the SCCC block SCB1 is mapped with (B1, B6), theSCCC block SCB2 is mapped with (B2, B7), the SCCC block SCB3 is mappedwith (B3, B8), the SCCC block SCB4 is mapped with (B4, B9), and the SCCCblock SCB5 is mapped with (B5, B10). The M/H block that is outputtedfrom the SCCC block-M/H block converter 516 is configured of mobileservice data and FEC redundancy. In the present invention, the mobileservice data as well as the FEC redundancy of the M/H block will becollectively considered as mobile service data.

Group Formatter

The group formatter 303 inserts data of M/H blocks outputted from theblock processor 302 to the corresponding M/H blocks within the datagroup, which is formed in accordance with a pre-defined rule. Also, inassociation with the data-deinterleaving process, the group formatter303 inserts various place holders (or known data place holders) in thecorresponding region within the data group. More specifically, apartfrom the encoded mobile service data outputted from the block processor302, the group formatter 303 also inserts MPEG header place holders,non-systematic RS parity place holders, main service data place holders,which are associated with the data deinterleaving in a later process, asshown in FIG. 5.

Herein, the main service data place holders are inserted because themobile service data bytes and the main service data bytes arealternately mixed with one another in regions B to D based upon theinput of the data deinterleaver, as shown in FIG. 5. For example, basedupon the data outputted after data deinterleaving, the place holder forthe MPEG header may be allocated at the very beginning of each packet.Also, in order to configure an intended group format, dummy bytes mayalso be inserted. Furthermore, the group formatter 303 insertsinitialization data (i.e., trellis initialization byte) of the trellisencoding module 256 in the corresponding regions. For example, theinitialization data may be inserted in the beginning of the known datasequence. The initialization data is used for initializing memorieswithin the trellis encoding module 256, and is not transmitted to thereceiving system.

Additionally, the group formatter 303 may also insert signalinginformation, which are encoded and outputted from the signaling encoder304, in corresponding regions within the data group. At this point,reference may be made to the signaling information when the groupformatter 303 inserts each data type and respective place holders in thedata group. The process of encoding the signaling information andinserting the encoded signaling information to the data group will bedescribed in detail in a later process.

After inserting each data type and respective place holders in the datagroup, the group formatter 303 may deinterleave the data and respectiveplace holders, which have been inserted in the data group, as an inverseprocess of the data interleaver, thereby outputting the deinterleaveddata and respective place holders to the packet formatter 305. The groupformatter 303 may include a group format organizer 527, and a datadeinterleaver 529, as shown in FIG. 31. The group format organizer 527inserts data and respective place holders in the corresponding regionswithin the data group, as described above. And, the data deinterleaver529 deinterleaves the inserted data and respective place holders as aninverse process of the data interleaver.

The packet formatter 305 removes the main service data place holders andthe RS parity place holders that were allocated for the deinterleavingprocess from the deinterleaved data being inputted. Then, the packetformatter 305 groups the remaining portion and inserts the 3-byte MPEGheader place holder in an MPEG header having a null packet PID (or anunused PID from the main service data packet). Furthermore, the packetformatter 305 adds a synchronization data byte at the beginning of each187-byte data packet. Also, when the group formatter 303 inserts knowndata place holders, the packet formatter 303 may insert actual knowndata in the known data place holders, or may directly output the knowndata place holders without any modification in order to make replacementinsertion in a later process. Thereafter, the packet formatter 305identifies the data within the packet-formatted data group, as describedabove, as a 188-byte unit mobile service data packet (i.e., MPEG TSpacket), which is then provided to the packet multiplexer 240.

Based upon the control of the controller 201, the packet multiplexer 240multiplexes the data group packet-formatted and outputted from thepacket formatter 306 and the main service data packet outputted from thepacket jitter mitigator 220. Then, the packet multiplexer 240 outputsthe multiplexed data packets to the data randomizer 251 of thepost-processor 250. More specifically, the controller 201 controls thetime-multiplexing of the packet multiplexer 240. If the packetmultiplexer 240 receives 118 mobile service data packets from the packetformatter 305, 37 mobile service data packets are placed before a placefor inserting VSB field synchronization. Then, the remaining 81 mobileservice data packets are placed after the place for inserting VSB fieldsynchronization. The multiplexing method may be adjusted by diversevariables of the system design. The multiplexing method and multiplexingrule of the packet multiplexer 240 will be described in more detail in alater process.

Also, since a data group including mobile service data in-between thedata bytes of the main service data is multiplexed (or allocated) duringthe packet multiplexing process, the shifting of the chronologicalposition (or place) of the main service data packet becomes relative.Also, a system object decoder (i.e., MPEG decoder) for processing themain service data of the receiving system, receives and decodes only themain service data and recognizes the mobile service data packet as anull data packet.

Therefore, when the system object decoder of the receiving systemreceives a main service data packet that is multiplexed with the datagroup, a packet jitter occurs.

At this point, since a multiple-level buffer for the video data existsin the system object decoder and the size of the buffer is relativelylarge, the packet jitter generated from the packet multiplexer 240 doesnot cause any serious problem in case of the video data. However, sincethe size of the buffer for the audio data in the object decoder isrelatively small, the packet jitter may cause considerable problem. Morespecifically, due to the packet jitter, an overflow or underflow mayoccur in the buffer for the main service data of the receiving system(e.g., the buffer for the audio data). Therefore, the packet jittermitigator 220 re-adjusts the relative position of the main service datapacket so that the overflow or underflow does not occur in the systemobject decoder.

In the present invention, examples of repositioning places for the audiodata packets within the main service data in order to minimize theinfluence on the operations of the audio buffer will be described indetail. The packet jitter mitigator 220 repositions the audio datapackets in the main service data section so that the audio data packetsof the main service data can be as equally and uniformly aligned andpositioned as possible. Additionally, when the positions of the mainservice data packets are relatively re-adjusted, associated programclock reference (PCR) values may also be modified accordingly. The PCRvalue corresponds to a time reference value for synchronizing the timeof the MPEG decoder. Herein, the PCR value is inserted in a specificregion of a TS packet and then transmitted.

In the example of the present invention, the packet jitter mitigator 220also performs the operation of modifying the PCR value. The output ofthe packet jitter mitigator 220 is inputted to the packet multiplexer240. As described above, the packet multiplexer 240 multiplexes the mainservice data packet outputted from the packet jitter mitigator 220 withthe mobile service data packet outputted from the pre-processor 230 intoa burst structure in accordance with a pre-determined multiplexing rule.Then, the packet multiplexer 240 outputs the multiplexed data packets tothe data randomizer 251 of the post-processor 250.

If the inputted data correspond to the main service data packet, thedata randomizer 251 performs the same randomizing process as that of theconventional randomizer. More specifically, the synchronization bytewithin the main service data packet is deleted. Then, the remaining 187data bytes are randomized by using a pseudo random byte generated fromthe data randomizer 251. Thereafter, the randomized data are outputtedto the RS encoder/non-systematic RS encoder 252.

On the other hand, if the inputted data correspond to the mobile servicedata packet, the data randomizer 251 may randomize only a portion of thedata packet. For example, if it is assumed that a randomizing processhas already been performed in advance on the mobile service data packetby the pre-processor 230, the data randomizer 251 deletes thesynchronization byte from the 4-byte MPEG header included in the mobileservice data packet and, then, performs the randomizing process only onthe remaining 3 data bytes of the MPEG header. Thereafter, therandomized data bytes are outputted to the RS encoder/non-systematic RSencoder 252. More specifically, the randomizing process is not performedon the remaining portion of the mobile service data excluding the MPEGheader. In other words, the remaining portion of the mobile service datapacket is directly outputted to the RS encoder/non-systematic RS encoder252 without being randomized. Also, the data randomizer 251 may or maynot perform a randomizing process on the known data (or known data placeholders) and the initialization data included in the mobile service datapacket.

The RS encoder/non-systematic RS encoder 252 performs an RS encodingprocess on the data being randomized by the data randomizer 251 or onthe data bypassing the data randomizer 251, so as to add 20 bytes of RSparity data. Thereafter, the processed data are outputted to the datainterleaver 253. Herein, if the inputted data correspond to the mainservice data packet, the RS encoder/non-systematic RS encoder 252performs the same systematic RS encoding process as that of theconventional broadcasting system, thereby adding the 20-byte RS paritydata at the end of the 187-byte data. Alternatively, if the inputteddata correspond to the mobile service data packet, the RSencoder/non-systematic RS encoder 252 performs a non-systematic RSencoding process. At this point, the 20-byte RS parity data obtainedfrom the non-systematic RS encoding process are inserted in apre-decided parity byte place within the mobile service data packet.

The data interleaver 253 corresponds to a byte unit convolutionalinterleaver. The output of the data interleaver 253 is inputted to theparity replacer 254 and to the non-systematic RS encoder 255.

Meanwhile, a process of initializing a memory within the trellisencoding module 256 is primarily required in order to decide the outputdata of the trellis encoding module 256, which is located after theparity replacer 254, as the known data pre-defined according to anagreement between the receiving system and the transmitting system. Morespecifically, the memory of the trellis encoding module 256 should firstbe initialized before the received known data sequence istrellis-encoded.

At this point, the beginning portion of the known data sequence that isreceived corresponds to the initialization data and not to the actualknown data. Herein, the initialization data has been included in thedata by the group formatter within the pre-processor 230 in an earlierprocess. Therefore, the process of replacing the initialization datawith memory values within the trellis encoding module 256 are requiredto be performed immediately before the inputted known data sequence istrellis-encoded.

More specifically, the initialization data are replaced with the memoryvalue within the trellis encoding module 256, thereby being inputted tothe trellis encoding module 256. At this point, the memory valuereplacing the initialization data are process with (or calculated by) anexclusive OR (XOR) operation with the respective memory value within thetrellis encoding module 256, so as to be inputted to the correspondingmemory. Therefore, the corresponding memory is initialized to ‘0’.Additionally, a process of using the memory value replacing theinitialization data to re-calculate the RS parity, so that there-calculated RS parity value can replace the RS parity being outputtedfrom the data interleaver 253, is also required.

Therefore, the non-systematic RS encoder 255 receives the mobile servicedata packet including the initialization data from the data interleaver253 and also receives the memory value from the trellis encoding module256.

Among the inputted mobile service data packet, the initialization dataare replaced with the memory value, and the RS parity data that areadded to the mobile service data packet are removed and processed withnon-systematic RS encoding. Thereafter, the new RS parity obtained byperforming the non-systematic RS encoding process is outputted to theparity replacer 255. Accordingly, the parity replacer 255 selects theoutput of the data interleaver 253 as the data within the mobile servicedata packet, and the parity replacer 255 selects the output of thenon-systematic RS encoder 255 as the RS parity. The selected data arethen outputted to the trellis encoding module 256.

Meanwhile, if the main service data packet is inputted or if the mobileservice data packet, which does not include any initialization data thatare to be replaced, is inputted, the parity replacer 254 selects thedata and RS parity that are outputted from the data interleaver 253.Then, the parity replacer 254 directly outputs the selected data to thetrellis encoding module 256 without any modification. The trellisencoding module 256 converts the byte-unit data to symbol units andperforms a 12-way interleaving process so as to trellis-encode thereceived data. Thereafter, the processed data are outputted to thesynchronization multiplexer 260.

FIG. 32 illustrates a detailed diagram of one of 12 trellis encodersincluded in the trellis encoding module 256. Herein, the trellis encoderincludes first and second multiplexers 531 and 541, first and secondexclusive OR (XOR) gates 532 and 542, and first to third memories 533,542, and 544.

More specifically, the first to third memories 533, 542, and 544 areinitialized by the memory value instead of the initialization data fromthe parity replacer 254. More specifically, when the first symbol (i.e.,two bits), which are converted from initialization data (i.e., eachtrellis initialization data byte), are inputted, the input bits of thetrellis encoder will be replaced by the memory values of the trellisencoder, as shown in FIG. 32.

Since 2 symbols (i.e., 4 bits) are required for trellis initialization,the last 2 symbols (i.e., 4 bits) from the trellis initialization bytesare not used for trellis initialization and are considered as a symbolfrom a known data byte and processed accordingly.

When the trellis encoder is in the initialization mode, the input comesfrom an internal trellis status (or state) and not from the parityreplacer 254. When the trellis encoder is in the normal mode, the inputsymbol (X2X1) provided from the parity replacer 254 will be processed.The trellis encoder provides the converted (or modified) input data fortrellis initialization to the non-systematic RS encoder 255.

More specifically, when a selection signal designates a normal mode, thefirst multiplexer 531 selects an upper bit X2 of the input symbol. And,when a selection signal designates an initialization mode, the firstmultiplexer 531 selects the output of the first memory 533 and outputsthe selected output data to the first XOR gate 532. The first XOR gate532 performs XOR operation on the output of the first multiplexer 531and the output of the first memory 533, thereby outputting the addedresult to the first memory 533 and, at the same time, as a mostsignificant (or uppermost) bit Z2. The first memory 533 delays theoutput data of the first XOR gate 532 by 1 clock, thereby outputting thedelayed data to the first multiplexer 531 and the first XOR gate 532.

Meanwhile, when a selection signal designates a normal mode, the secondmultiplexer 541 selects a lower bit X1 of the input symbol. And, when aselection signal designates an initialization mode, the secondmultiplexer 541 selects the output of the second memory 542, therebyoutputting the selected result to the second XOR gate 543 and, at thesame time, as a lower bit Z1. The second XOR gate 543 performs XORoperation on the output of the second multiplexer 541 and the output ofthe second memory 542, thereby outputting the added result to the thirdmemory 544. The third memory 544 delays the output data of the secondXOR gate 543 by 1 clock, thereby outputting the delayed data to thesecond memory 542 and, at the same time, as a least significant (orlowermost) bit Z0. The second memory 542 delays the output data of thethird memory 544 by 1 clock, thereby outputting the delayed data to thesecond XOR gate 543 and the second multiplexer 541.

The select signal designates an initialization mode during the first twosymbols that are converted from the initialization data.

For example, when the select signal designates an initialization mode,the first XOR gate 532 performs an XOR operation on the value of thefirst memory 533, which is provided through the first multiplexer 531,and on a memory value that is directly provided from the first memory533. That is, the first XOR gate 532 performs an XOR operation on 2 bitshaving the same value. Generally, when only one of the two bitsbelonging to the operand is ‘1’, the result of the XOR gate is equal to‘1’. Otherwise, the result of the XOR gate becomes equal to ‘0’.Therefore, when the value of the first memory 533 is processed with anXOR operation, the result is always equal to ‘0’. Furthermore, since theoutput of the first XOR gate 532, i.e., ‘0’, is inputted to the firstmemory 533, the first memory 533 is initialized to ‘0’.

Similarly, when the select signal designates an initialization mode, thesecond XOR gate 543 performs an XOR operation on the value of the secondmemory 542, which is provided through the second multiplexer 541, and ona memory value that is directly provided from the second memory 542.Therefore, the output of the second XOR gate 543 is also always equal to‘0’. Since the output of the second XOR gate 543, i.e., ‘0’, is inputtedto the third memory 544, the third memory 544 is also initialized to‘0’. The output of the third memory 544 is inputted to the second memory542 in the next clock, thereby initializing the second memory 542 to‘0’. In this case also, the select signal designates the initializationmode.

More specifically, when the first symbol being converted from theinitialization data byte replaces the values of the first memory 533 andthe second memory 542, thereby being inputted to the trellis encoder,each of the first and third memories 533 and 544 within the trellisencoder is initialized to ‘00’. Following the process, when the secondsymbol being converted from the initialization data byte replaces thevalues of the first memory 533 and the second memory 542, thereby beinginputted to the trellis encoder, each of the first, second, and thirdmemories 533, 542, and 544 within the trellis encoder is initialized to‘000’.

As described above, 2 symbols are required to initialize the memory ofthe trellis encoder. At this point, while the select signal designatesan initialization mode, the output bits (X2′X1′) of the first and secondmemories 533 and 542 are inputted to the non-systematic RS encoder 255,so as to perform a new RS parity calculation process.

The synchronization multiplexer 260 inserts a field synchronizationsignal and a segment synchronization signal to the data outputted fromthe trellis encoding module 256 and, then, outputs the processed data tothe pilot inserter 271 of the transmission unit 270. Herein, the datahaving a pilot inserted therein by the pilot inserter 271 are modulatedby the modulator 272 in accordance with a pre-determined modulatingmethod (e.g., a VSB method). Thereafter, the modulated data aretransmitted to each receiving system though the radio frequency (RF)up-converter 273.

Multiplexing Method of Packet Multiplexer

Data of the error correction encoded and 1/H-rate encoded primary RSframe (i.e., when the RS frame mode value is equal to ‘00’) orprimary/secondary RS frame (i.e., when the RS frame mode value is equalto ‘01’), are divided into a plurality of data groups by the groupformatter 303. Then, the divided data portions are assigned to at leastone of regions A to D of each data group or to an M/H block among theM/H blocks B1 to B10, thereby being deinterleaved. Then, thedeinterleaved data group passes through the packet formatter 305,thereby being multiplexed with the main service data by the packetmultiplexer 240 based upon a de-decided multiplexing rule. The packetmultiplexer 240 multiplexes a plurality of consecutive data groups, sothat the data groups are assigned to be spaced as far apart from oneanother as possible within the sub-frame. For example, when it isassumed that 3 data groups are assigned to a sub-frame, the data groupsare assigned to a 1^(st) slot (Slot #0), a 5^(th) slot (Slot #4), and a9^(th) slot (Slot #8) in the sub-frame, respectively.

As described-above, in the assignment of the plurality of consecutivedata groups, a plurality of parades are multiplexed and outputted so asto be spaced as far apart from one another as possible within asub-frame. For example, the method of assigning data groups and themethod of assigning parades may be identically applied to all sub-framesfor each M/H frame or differently applied to each M/H frame.

FIG. 10 illustrates an example of a plurality of data groups included ina single parade, wherein the number of data groups included in asub-frame is equal to ‘3’, and wherein the data groups are assigned toan M/H frame by the packet multiplexer 240. Referring to FIG. 10, 3 datagroups are sequentially assigned to a sub-frame at a cycle period of 4slots. Accordingly, when this process is equally performed in the 5sub-frames included in the corresponding M/H frame, 15 data groups areassigned to a single M/H frame. Herein, the 15 data groups correspond todata groups included in a parade.

When data groups of a parade are assigned as shown in FIG. 10, thepacket multiplexer 240 may either assign main service data to each datagroup, or assign data groups corresponding to different parades betweeneach data group. More specifically, the packet multiplexer 240 mayassign data groups corresponding to multiple parades to one M/H frame.Basically, the method of assigning data groups corresponding to multipleparades is very similar to the method of assigning data groupscorresponding to a single parade. In other words, the packet multiplexer240 may assign data groups included in other parades to an M/H frameaccording to a cycle period of 4 slots. At this point, data groups of adifferent parade may be sequentially assigned to the respective slots ina circular method. Herein, the data groups are assigned to slotsstarting from the ones to which data groups of the previous parade havenot yet been assigned. For example, when it is assumed that data groupscorresponding to a parade are assigned as shown in FIG. 10, data groupscorresponding to the next parade may be assigned to a sub-frame startingeither from the 12^(th) slot of a sub-frame.

FIG. 11 illustrates an example of assigning and transmitting 3 parades(Parade #0, Parade #1, and Parade #2) to an M/H frame. For example, whenthe 1^(st) parade (Parade #0) includes 3 data groups for each sub-frame,the packet multiplexer 240 may obtain the positions of each data groupswithin the sub-frames by substituting values ‘0’ to ‘2’ for i inEquation 1. More specifically, the data groups of the 1^(st) parade(Parade #0) are sequentially assigned to the 1^(st), 5^(th), and 9^(th)slots (Slot #0, Slot #4, and Slot #8) within the sub-frame. Also, whenthe 2^(nd) parade includes 2 data groups for each sub-frame, the packetmultiplexer 240 may obtain the positions of each data groups within thesub-frames by substituting values ‘3’ and ‘4’ for i in Equation 1. Morespecifically, the data groups of the 2^(nd) parade (Parade #1) aresequentially assigned to the 2^(nd) and 12^(th) slots (Slot #3 and Slot#11) within the sub-frame. Finally, when the 3^(rd) parade includes 2data groups for each sub-frame, the packet multiplexer 240 may obtainthe positions of each data groups within the sub-frames by substitutingvalues ‘5’ and ‘6’ for in Equation 1. More specifically, the data groupsof the 3rd parade (Parade #2) are sequentially assigned and outputted tothe 7^(th) and 11^(th) slots (Slot #6 and Slot #10) within thesub-frame.

As described above, the packet multiplexer 240 may multiplex and outputdata groups of multiple parades to a single M/H frame, and, in eachsub-frame, the multiplexing process of the data groups may be performedserially with a group space of 4 slots from left to right. Therefore, anumber of groups of one parade per sub-frame (NOG) may correspond to anyone integer from ‘1’ to ‘8’. Herein, since one M/H frame includes 5sub-frames, the total number of data groups within a parade that can beallocated to an M/H frame may correspond to any one multiple of ‘5’ranging from ‘5’ to ‘40’.

Processing Signaling Information

The present invention assigns signaling information areas for insertingsignaling information to some areas within each data group. FIG. 33illustrates an example of assigning signaling information areas forinserting signaling information starting from the 1^(st) segment of the4^(th) M/H block (B4) to a portion of the 2^(nd) segment. Morespecifically, 276(=207+69) bytes of the 4^(th) M/H block (B4) in eachdata group are assigned as the signaling information area. In otherwords, the signaling information area consists of 207 bytes of the1^(st) segment and the first 69 bytes of the 2^(nd) segment of the4^(th) M/H block (B4). For example, the 1^(st) segment of the 4^(th) M/Hblock (B4) corresponds to the 17^(th) or 173^(rd) segment of a VSBfield.

The signaling information that is to be inserted in the signalinginformation area is FEC-encoded by the signaling encoder 304, therebyinputted to the group formatter 303. The signaling information mayinclude a transmission parameter which is included in the payload regionof an OM packet, and then received to the demultiplexer 210.

The group formatter 303 inserts the signaling information, which isFEC-encoded and outputted by the signaling encoder 304, in the signalinginformation area within the data group. Herein, the signalinginformation may be identified by two different types of signalingchannels: a transmission parameter channel (TPC) and a fast informationchannel (FIC).

Herein, the TPC data corresponds to signaling information includingtransmission parameters, such as RS frame information, RS encodinginformation, FIC information, data group information, SCCC information,and M/H frame information and so on. However, the TPC data presentedherein is merely exemplary. And, since the adding or deleting ofsignaling information included in the TPC may be easily adjusted andmodified by one skilled in the art, the present invention will,therefore, not be limited to the examples set forth herein.

Furthermore, the FIC data is provided to enable a fast serviceacquisition of data receivers, and the FIC data includes cross layerinformation between the physical layer and the upper layer(s).

FIG. 34 illustrates a detailed block diagram of the signaling encoder304 according to the present invention. Referring to FIG. 34, thesignaling encoder 304 includes a TPC encoder 561, an FIC encoder 562, ablock interleaver 563, a multiplexer 564, a signaling randomizer 565,and an iterative turbo encoder 566.

The TPC encoder 561 receives 10-bytes of TPC data and performs(18,10)-RS encoding on the 10-bytes of TPC data, thereby adding 8 bytesof parity data to the 10 bytes of TPC data. The 18 bytes of RS-encodedTPC data are outputted to the multiplexer 564.

The FIC encoder 562 receives 37-bytes of FIC data and performs(51,37)-RS encoding on the 37-bytes of FIC data, thereby adding 14 bytesof parity data to the 37 bytes of FIC data. Thereafter, the 51 bytes ofRS-encoded FIC data are inputted to the block interleaver 563, therebybeing interleaved in predetermined block units. Herein, the blockinterleaver 563 corresponds to a variable length block interleaver. Theblock interleaver 563 interleaves the FIC data within each sub-frame inTNoG(column)×51(row) block units and then outputs the interleaved datato the multiplexer 564. Herein, the TNoG corresponds to the total numberof data groups being assigned to a sub-frame. The block interleaver 563is synchronized with the first set of FIC data in each sub-frame.

The block interleaver 563 writes 51 bytes of incoming (or inputted) RScodewords in a row direction (i.e., row-by-row) and left-to-right andup-to-down directions and reads 51 bytes of RS codewords in a columndirection (i.e., column-by-column) and left-to-right and up-to-downdirections, thereby outputting the RS codewords.

The multiplexer 564 multiplexes the RS-encoded TPC data from the TPCencoder 561 and the block-interleaved FIC data from the blockinterleaver 563 along a time axis. Then, the multiplexer 564 outputs 69bytes of the multiplexed data to the signaling randomizer 565. Thesignaling randomizer 565 randomizes the multiplexed data and outputs therandomized data to the iterative turbo encoder 566. The signalingrandomizer 565 may use the same generator polynomial of the randomizerused for mobile service data. Also, initialization occurs in each datagroup.

The iterative turbo encoder 566 corresponds to an inner encoderperforming iterative turbo encoding in a PCCC method on the randomizeddata (i.e., signaling information data). The iterative turbo encoder 566may include 6 even component encoders and 6 odd component encoders.

FIG. 35 illustrates an example of a syntax structure of TPC data beinginputted to the TPC encoder 561. The TPC data are inserted in thesignaling information area of each data group and then transmitted. TheTPC data may include a sub-frame_number field, a slot_number field, aparade_id field, a starting_group_number (SGN) field, a number_of_groups(NoG) field, a parade_repetition_cycle (PRC) field, an RS_frame_modefield, an RS_code_mode_primary field, an RS_code_mode_secondary field,an SCCC_block_mode field, an SCCC_outer_code_mode_A field, anSCCC_outer_code_mode_B field, an SCCC_outer_code_mode_C field, anSCCC_outer_code_mode_D field, an FIC_version field, aparade_continuity_counter field, and a TNoG field.

The Sub-Frame_number field corresponds to the current Sub-Frame numberwithin the M/H frame, which is transmitted for M/H framesynchronization. The value of the Sub-Frame_number field may range from0 to 4. The Slot_number field indicates the current slot number withinthe sub-frame, which is transmitted for M/H frame synchronization. Also,the value of the Sub-Frame number field may range from 0 to 15. TheParade_id field identifies the parade to which this group belongs. Thevalue of this field may be any 7-bit value. Each parade in a M/Htransmission shall have a unique Parade_id field.

Communication of the Parade_id between the physical layer and themanagement layer may be performed by means of an Ensemble_id fieldformed by adding one bit to the left of the Parade_id field. If theEnsemble_id field is used for the primary Ensemble delivered throughthis parade, the added MSB shall be equal to ‘0’. Otherwise, if theEnsemble_id field is used for the secondary ensemble, the added MSBshall be equal to ‘1’. Assignment of the Parade_id field values mayoccur at a convenient level of the system, usually in the managementlayer. The starting_group_number (SGN) field shall be the firstSlot_number for a parade to which this group belongs, as determined byEquation 1 (i.e., after the Slot numbers for all preceding parades havebeen calculated). The SGN and NoG shall be used according to Equation 1to obtain the slot numbers to be allocated to a parade within thesub-frame.

The number_of_Groups (NoG) field shall be the number of groups in asub-frame assigned to the parade to which this group belongs, minus 1,e.g., NoG=0 implies that one group is allocated (or assigned) to thisparade in a sub-frame. The value of NoG may range from 0 to 7. Thislimits the amount of data that a parade may take from the main (legacy)service data, and consequently the maximum data that can be carried byone parade. The slot numbers assigned to the corresponding Parade can becalculated from SGN and NoG, using Equation 1. By taking each parade insequence, the specific slots for each parade will be determined, andconsequently the SGN for each succeeding parade. For example, if for aspecific parade SGN=3 and NoG=3 (010b for 3-bit field of NoG),substituting i=3, 4, and 5 in Equation 1 provides slot numbers 12, 2,and 6.

The Parade_repetition_cycle (PRC) field corresponds to the cycle timeover which the parade is transmitted, minus 1, specified in units of M/Hframes, as described in Table 12.

TABLE 12 PRC Description 000 This parade shall be transmitted once everyM/H frame. 001 This parade shall be transmitted once every 2 M/H frames.010 This parade shall be transmitted once every 3 M/H frames. 011 Thisparade shall be transmitted once every 4 M/H frames. 100 This paradeshall be transmitted once every 5 M/H frames. 101 This parade shall betransmitted once every 6 M/H frames. 110 This parade shall betransmitted once every 7 M/H frames. 111 Reserved

For example, if PRC field value is equal to ‘001’, this indicates thatthe parade shall be transmitted once every 2 M/H frame.

The RS_Frame_mode field shall be as defined in Table 1. TheRS_Frame_mode field represents that one parade transmits one RS frame ortwo RS frames.

The RS_code_mode_primary field shall be the RS code mode for the primaryRS frame. Herein, the RS_code_mode_primary field is defined in Table 6.

The RS_code_mode_secondary field shall be the RS code mode for thesecondary RS frame. Herein, the RS_code_mode_secondary field is definedin Table 6.

The SCCC_Block_mode field represents how M/H blocks within a data groupare assigned to SCCC block. The SCCC_Block_mode field shall be asdefined in Table 7.

The SCCC_outer_code_mode_A field corresponds to the SCCC outer code modefor Region A within a data group. The SCCC outer code mode is defined inTable 8.

The SCCC_outer_code_mode_B field corresponds to the SCCC outer code modefor Region B within the data group. The SCCC_outer_code_mode_C fieldcorresponds be the SCCC outer code mode for Region C within the datagroup. And, the SCCC_outer_code_mode_D field corresponds to the SCCCouter code mode for Region D within the data group.

The FIC_version field represents a version of FIC data.

The Parade_continuity_counter field counter may increase from 0 to 15and then repeat its cycle. This counter shall increment by 1 every(PRC+1) M/H frames. For example, as shown in Table 12, PRC=011 (decimal3) implies that Parade_continuity_counter increases every fourth M/Hframe.

The TNoG field may be identical for all sub-frames in an M/H Frame.

However, the information included in the TPC data presented herein ismerely exemplary. And, since the adding or deleting of informationincluded in the TPC may be easily adjusted and modified by one skilledin the art, the present invention will, therefore, not be limited to theexamples set forth herein.

Since the TPC data (excluding the Sub-Frame_number field and theSlot_number field) for each parade do not change their values during anM/H frame, the same information is repeatedly transmitted through allM/H groups belonging to the corresponding parade during an M/H frame.This allows very robust and reliable reception of the TPC data. Becausethe Sub-Frame_number and the Slot_number are increasing counter values,they also are robust due to the transmission of regularly expectedvalues.

Furthermore, the FIC data is provided to enable a fast serviceacquisition of data receivers, and the FIC information includes crosslayer information between the physical layer and the upper layer(s).

FIG. 36 illustrates an example of a transmission scenario of the TPCdata and the FIC data. The values of the Sub-Frame_number field,Slot_number field, Parade_id field, Parade_repetition_cycle field, andParade_continuity_counter field may corresponds to the current M/H framethroughout the sub-frames within a specific M/H frame. Some of TPCparameters and FIC data are signaled in advance.

The SGN, NoG and all FEC modes may have values corresponding to thecurrent M/H frame in the first two sub-frames. The SGN, NoG and all FECmodes may have values corresponding to the frame in which the paradenext appears throughout the 3^(rd), 4^(th) and 5^(th) sub-frames of thecurrent M/H frame. This enables the M/H receivers to receive (oracquire) the transmission parameters in advance very reliably.

For example, when Parade_repetition_cycle=‘000’, the values of the3^(rd), 4^(th), and 5^(th) sub-frames of the current M/H framecorrespond to the next M/H frame. Also, whenParade_repetition_cycle=‘011’, the values of the 3^(rd), 4^(th), and5^(th) sub-frames of the current M/H frame correspond to the 4^(th) M/Hframe and beyond.

The FIC_version field and the FIC_data field may have values that applyto the current M/H Frame during the 1^(st) sub-frame and the 2^(nd)sub-frame, and they shall have values corresponding to the M/H frameimmediately following the current M/H frame during the 3^(rd), 4^(th),and 5^(th) sub-frames of the current M/H frame.

Meanwhile, the receiving system may turn the power on only during a slotto which the data group of the designated (or desired) parade isassigned, and the receiving system may turn the power off during theremaining slots, thereby reducing power consumption of the receivingsystem. Such characteristic is particularly useful in portable or mobilereceivers, which require low power consumption. For example, it isassumed that data groups of a 1^(st) parade with NOG=3, a 2^(nd) paradewith NOG=2, and a 3^(rd) parade with NOG=3 are assigned to one M/Hframe, as shown in FIG. 37. It is also assumed that the user hasselected a mobile service included in the 1^(st) parade using the keypadprovided on the remote controller or terminal. In this case, thereceiving system turns the power on only during a slot that data groupsof the 1^(st) parade is assigned, as shown in FIG. 37, and turns thepower off during the remaining slots, thereby reducing powerconsumption, as described above. At this point, the power is required tobe turned on briefly earlier than the slot to which the actualdesignated data group is assigned (or allocated). This is to enable thetuner or demodulator to converge in advance.

Assignment of Known Data (or Training Signal)

In addition to the payload data, the M/H transmission system insertslong and regularly spaced training sequences into each group. Theregularity is an especially useful feature since it provides thegreatest possible benefit for a given number of training symbols inhigh-Doppler rate conditions. The length of the training sequences isalso chosen to allow fast acquisition of the channel during burstedpower-saving operation of the demodulator. Each group contains 6training sequences. The training sequences are specified beforetrellis-encoding. The training sequences are then trellis-encoded andthese trellis-encoded sequences also are known sequences. This isbecause the trellis encoder memories are initialized to pre-determinedvalues at the beginning of each sequence. The form of the 6 trainingsequences at the byte level (before trellis-encoding) is shown in FIG.38. This is the arrangement of the training sequence at the groupformatter 303. FIG. 73 illustrates an example of a known data (training)sequence represented using numbers at the byte level according to thepresent invention. In FIG. 73, known data (training) bytes includetrellis initialization bytes.

The 1^(st) training sequence is located at the last 2 segments of the3^(rd) M/H block (B3). The 2^(nd) training sequence may be inserted atthe 2^(nd) and 3^(rd) segments of the 4^(th) M/H block (B4). The 2^(nd)training sequence is next to the signaling area, as shown in FIG. 5.Then, the 3^(rd) training sequence, the 4^(th) training sequence, the5^(th) training sequence, and the 6^(th) training sequence may be placedat the last 2 segments of the 4^(th), 5^(th), 6^(th) and 7^(th) M/Hblocks (B4, B5, B6, and B7), respectively. As shown in FIG. 38, the1^(st) training sequence, the 3^(rd) training sequence, the 4^(th)training sequence, the 5^(th) training sequence, and the 6^(th) trainingsequence are spaced 16 segments apart from one another. Referring toFIG. 38, the dotted area indicates trellis initialization data bytes,the lined area indicates training data bytes, and the white areaincludes other bytes such as the FEC-coded M/H service data bytes,FEC-coded signaling data, main service data bytes, RS parity data bytes(for backwards compatibility with legacy ATSC receivers) and/or dummydata bytes.

FIG. 39 illustrates the training sequences (at the symbol level) aftertrellis-encoding by the trellis encoder.

Referring to FIG. 39, the dotted area indicates data segment syncsymbols, the lined area indicates training data symbols, and the whitearea includes other symbols, such as FEC-coded mobile service datasymbols, FEC-coded signaling data, main service data symbols, RS paritydata symbols (for backwards compatibility with legacy ATSC receivers),dummy data symbols, trellis initialization data symbols, and/or thefirst part of the training sequence data symbols. Due to theintra-segment interleaving of the trellis encoder, various types of datasymbols will be mixed in the white area.

After the trellis-encoding process, the last 1416 (=588+828) symbols ofthe 1^(st) training sequence, the 3^(rd) training sequence, the 4^(th)training sequence, the 5^(th) training sequence, and the 6^(th) trainingsequence commonly share the same data pattern. Including the datasegment synchronization symbols in the middle of and after eachsequence, the total length of each common training pattern is 1424symbols. The 2^(nd) training sequence has a first 528-symbol sequenceand a second 528-symbol sequence that have the same data pattern. Morespecifically, the 528-symbol sequence is repeated after the 4-symboldata segment synchronization signal. At the end of each trainingsequence, the memory contents of the twelve modified trellis encodersshall be set to zero (0).

FIG. 74 illustrates an example of a training sequence represented usingnumbers at the symbol according to the present invention. In FIG. 74, aVSB level value −7 is mapped to number 0, a VSB level value −5 is mappedto number 1, a VSB level value −3 is mapped to number 2, a VSB levelvalue −1 is mapped to number 3, a VSB level value 1 is mapped to number4, a VSB level value 3 is mapped to number 5, a VSB level value 5 ismapped to number 6, and a VSB level value 7 is mapped to number 7.

Receiving System

FIG. 40 is a block diagram illustrating a receiving system according toan embodiment of the present invention.

The receiving system of FIG. 40 includes a tuner 1301, a demodulatingunit 1302, a demultiplexer 1303, a program table buffer 1304, a programtable decoder 1305, a program table storage unit 1306, a data handler1307, a middleware engine 1308, an A/V decoder 1309, an A/Vpost-processor 1310, an application manager 1311, and a user interface1314. The application manager 1311 may include a channel manager 1312and a service manager 1313.

In FIG. 40, solid lines indicate data flows and dotted lines indicatecontrol flows.

The tuner 1301 tunes to a frequency of a specific channel through any ofan antenna, a cable, or a satellite and down-converts the frequency toan Intermediate Frequency (IF) signal and outputs the IF signal to thedemodulating unit 1302. Here, the tuner 1301 is controlled by thechannel manager 1312 in the application manager 1311 and reports theresult and strength of a broadcast signal of the tuned channel to thechannel manager 1312. Data received through the frequency of thespecific channel includes main service data, mobile service data, atransmission parameter, and program table information for decoding themain service data and the mobile service data.

The demodulating unit 1302 performs VSB demodulation, channelequalization, etc., on the signal output from the tuner 1301 andidentifies and separately outputs main service data and mobile servicedata. The demodulating unit 1302 will be described in detail in a later.

On the other hand, the transmitter can transmit signaling information(or TPC information) including transmission parameters by inserting thesignaling information into at least one of a field synchronizationregion, a known data region, and a mobile service data region.Accordingly, the demodulating unit 1302 can extract the transmissionparameters from the field synchronization region, the known data region,and the mobile service data region.

The transmission parameters may include M/H frame information, sub-frameinformation, slot information, parade-related information (for example,a parade_id, a parade repeat period, etc.), information of data groupsin a sub-frame, RS frame mode information, RS code mode information,SCCC block mode information, SCCC outer code mode information, FICversion information, etc.

The demodulating unit 1302 performs block decoding, RS frame decoding,etc., using the extracted transmission parameters. For example, thedemodulating unit 1302 performs block decoding of each region in a datagroup with reference to SCCC-related information (for example, SCCCblock mode information or an SCCC outer code mode) included in thetransmission parameters and performs RS frame decoding of each regionincluded in the data group with reference to RS-related information (forexample, an RS code mode).

In the embodiment of the present invention, an RS frame including mobileservice data demodulated by the demodulating unit 1302 is input to thedemultiplexer 1303.

That is, data inputted to the demultiplexer 1303 has an RS frame dataformat as shown in FIG. 17( a) or FIG. 17( b). More specifically, the RSframe decoder of the demodulating unit 1302 performs the reverse of theencoding process performed at the RS frame encoder of the transmissionsystem to correct errors in the RS frame and then outputs theerror-corrected RS frame to a data derandomizer. The data derandomizerthen performs derandomizing on the error-corrected RS frame through thereverse of the randomizing process performed at the transmission systemto obtain an RS frame as shown in FIG. 17( a) or FIG. 17( b).

The demultiplexer 1303 may receive RS frames of all parades and may alsoreceive only an RS frame of a parade including a mobile service that theuser desires to receive through power supply control. For example, whenRS frames of all parades are received, the demultiplexer 1303 candemultiplex a parade including a mobile service that the user desires toreceive using a parade_id.

One parade carries one or two RS frames and one ensemble is mapped toone RS frame. Therefore, when one parade carries two RS frames, thedemultiplexer 1303 needs to identify an RS frame carrying an ensembleincluding mobile service data to be decoded from a parade containing amobile service that the user desires to receive. That is, when areceived single parade or a parade demultiplexed from a plurality ofparades carries a primary ensemble and a secondary ensemble, thedemultiplexer 1303 selects one of the primary and secondary ensembles.

In an embodiment, the demultiplexer 1303 can demultiplex an RS framecarrying an ensemble including mobile service data to be decoded usingan ensemble_id generated by adding one bit to a left position of theparade_id.

The demultiplexer 1303 refers to the M/H header of the M/H service datapacket within the RS frame corresponding to the ensemble including themobile service data that are to be decoded, thereby identifying when thecorresponding M/H service data packet is the program table informationor the IP datagram of the mobile service data. Alternatively, when theprogram table information and the mobile service data are bothconfigured in the form of IP datagrams, the demultiplexer 1303 may usethe IP address in order to identify the IP datagram of the program tableinformation and the mobile service data.

Herein, the identified program table information is outputted to theprogram table buffer 1304. And, audio/video/data streams are separatedfrom the IP datagram of mobile service data that are to be selectedamong the IP datagrams of the identified mobile service data, therebybeing respectively outputted to the A/V decoder 1309 and/or the datahandler 1307.

According to an embodiment of the present invention, when thestuff_indicator field within the M/H header of the M/H service datapacket indicates that stuffing bytes are inserted in the payload of thecorresponding M/H service data packet, the demultiplexer 1303 removesthe stuffing bytes from the payload of the corresponding M/H servicedata packet. Then, the demultiplexer 1303 identifies the program tableinformation and the mobile service data. Thereafter, the demultiplexer1303 identifies A/V/D streams from the identified mobile service data.

The program table buffer 1304 temporarily stores the section-typeprogram table information and then outputs the section-type programtable information to the program table decoder 1305.

The program table decoder 1305 identifies tables using a table_id and asection_length in the program table information and parses sections ofthe identified tables and produces and stores a database of the parsedresults in the program table storage unit 1306. For example, the programtable decoder 1305 collects sections having the same table identifier(table_id) to construct a table. The program table decoder 1305 thenparses the table and produces and stores a database of the parsedresults in the program table storage unit 1306.

The A/V decoder 1309 decodes the audio and video streams outputted fromthe demultiplexer 1303 using audio and video decoding algorithms,respectively. The decoded audio and video data is outputted to the A/Vpost-processor 1310.

Here, at least one of an AC-3 decoding algorithm, an MPEG 2 audiodecoding algorithm, an MPEG 4 audio decoding algorithm, an AAC decodingalgorithm, an AAC+ decoding algorithm, an HE AAC decoding algorithm, anAAC SBR decoding algorithm, an MPEG surround decoding algorithm, and aBSAC decoding algorithm can be used as the audio decoding algorithm andat least one of an MPEG 2 video decoding algorithm, an MPEG 4 videodecoding algorithm, an H.264 decoding algorithm, an SVC decodingalgorithm, and a VC-1 decoding algorithm can be used as the audiodecoding algorithm.

The data handler 8507 processes data stream packets required for databroadcasting among data stream packets separated (or identified) by thedemultiplexer 1303 and provides the processed data stream packets to themiddleware engine 1310 to allow the middleware engine 1310 to bemultiplexed them with A/V data. In an embodiment, the middleware engine1310 is a Java middleware engine.

The application manager 1311 receives a key input from the TV viewer anddisplays a Graphical User Interface (GUI) on the TV screen in responseto a viewer request through a User Interface (UI). The applicationmanager 1311 also writes and reads information regarding overall GUIcontrol of the TV, user requests, and TV system states to and from amemory (for example, NVRAM or flash memory). In addition, theapplication manager 1311 can receive parade-related information (forexample, a parade_id) from the demodulating unit 1302 to control thedemultiplexer 1303 to select an RS frame of a parade including arequired mobile service. The application manager 1311 can also receivean ensemble_id to control the demultiplexer 1303 to select an RS frameof an ensemble including mobile service data to be decoded from theparade. The application manager 1311 also controls the channel manager1312 to perform channel-related operations (for example, channel mapmanagement and program table decoder operations).

The channel manager 1312 manages physical and logical channel maps andcontrols the tuner 1301 and the program table decoder 1305 to respond toa channel-related request of the viewer. The channel manager alsorequests that the program table decoder 1305 parse a channel-relatedtable of a channel to be tuned and receives the parsing results from theprogram table decoder 1305.

Demodulating Unit within Receiving System

FIG. 41 illustrates an example of a demodulating unit in a digitalbroadcast receiving system according to the present invention. Thedemodulating unit of FIG. 41 uses known data information, which isinserted in the mobile service data section and, then, transmitted bythe transmitting system, so as to perform carrier synchronizationrecovery, frame synchronization recovery, and channel equalization,thereby enhancing the receiving performance. Also the demodulating unitmay turn the power on only during a slot to which the data group of thedesignated (or desired) parade is assigned, thereby reducing powerconsumption of the receiving system.

Referring to FIG. 41, the demodulating unit includes an operationcontroller 2000, a demodulator 2002, an equalizer 2003, a known sequencedetector 2004, a block decoder 2005, and a RS frame decoder 2006. Thedemodulating unit may further include a main service data processor2008. The main service data processor 2008 may include a datadeinterleaver, a RS decoder, and a data derandomizer. The demodulatingunit may further include a signaling decoder 2013. The receiving systemalso may further include a power controller 5000 for controlling powersupply of the demodulating unit.

More specifically, a frequency of a particular channel tuned by a tunerdown converts to an intermediate frequency (IF) signal. Then, thedown-converted data 2001 outputs the down-converted IF signal to thedemodulator 2002 and the known sequence detector 2004. At this point,the down-converted data 2001 is inputted to the demodulator 2002 and theknown sequence detector 2004 via analog/digital converter ADC (notshown). The ADC converts pass-band analog IF signal into pass-banddigital IF signal.

The demodulator 2002 performs self gain control, carrier recovery, andtiming recovery processes on the inputted pass-band digital IF signal,thereby modifying the IF signal to a base-band signal. Then, thedemodulator 2002 outputs the newly generated base-band signal to theequalizer 2003 and the known sequence detector 2004.

The equalizer 2003 compensates the distortion of the channel included inthe demodulated signal and then outputs the error-compensated signal tothe block decoder 2005.

At this point, the known sequence detector 2004 detects the knownsequence position information inserted by the transmitting end from theinput/output data of the demodulator 2002 (i.e., the data prior to thedemodulation process or the data after the demodulation process).Thereafter, the position information along with the symbol sequence ofthe known data, which are generated from the detected position, isoutputted to the operation controller 2000, the demodulator 2002, theequalizer 2003, and the signaling decoder 2013. Also, the known sequencedetector 2004 outputs a set of information to the block decoder 2005.This set of information is used to allow the block decoder 2005 of thereceiving system to identify the mobile service data that are processedwith additional encoding from the transmitting system and the mainservice data that are not processed with additional encoding.

In addition, although the connection status is not shown in FIG. 41, theinformation detected from the known sequence detector 2004 may be usedthroughout the entire receiving system and may also be used in the RSframe decoder 2006.

The data demodulated in the demodulator 2002 or the data equalized inthe channel equalizer 2003 is inputted to the signaling decoder 2013.The known data position information detected in the known sequencedetector 2004 is inputted to the signaling decoder 2013.

The signaling decoder 2013 extracts and decodes signaling information(e.g., TPC information, and FIC information), which inserted andtransmitted by the transmitting end, from the inputted data, the decodedsignaling information provides to blocks requiring the signalinginformation.

More specifically, the signaling decoder 2013 extracts and decodes TPCdata and FIC data, which inserted and transmitted by the transmittingend, from the equalized data, and then the decoded TPC data and FIC dataoutputs to the operation controller 2000, the known sequence detector2004, and the power controller 5000. For example, the TPC data and FICdata is inserted in a signaling information region of each data group,and then is transmitted to a receiving system.

The signaling decoder 2013 performs signaling decoding as an inverseprocess of the signaling encoder shown in FIG. 34, so as to extract TPCdata and FIC data. For example, the signaling decoder 2013 decodes theinputted data using the PCCC method and derandomizes the decoded data,thereby dividing the derandomized data into TPC data and FIC data. Atthis point, the signaling decoder 2013 performs RS-decoding on thedivided TPC data, so as to correct the errors occurring in the TPC data.Subsequently, the signaling decoder 2013 deinterleaves the divided FICdata and then performs RS-decoding on the deinterleaved FIC data, so asto correct the error occurring in the FIC data. The error-corrected TPCdata are then outputted to the operation controller 2000, the knownsequence detector 2004, and the power controller 5000.

The TPC data may also include a transmission parameter which is insertedinto the payload region of an OM packet by the service multiplexer 100,and then is transmitted to transmitter 200.

Herein, the TPC data may include RS frame information, SCCC information,M/H frame information, and so on, as shown in FIG. 35. The RS frameinformation may include RS frame mode information and RS code modeinformation. The SCCC information may include SCCC block modeinformation and SCCC outer code mode information. The M/H frameinformation may include M/H frame index information, and the TPC datamay include sub-frame count information, slot count information,parade_id information, SGN information, NoG information, and so on.

At this point, the signaling decoder 2013 can know the signalinginformation region within a data group by using the known datainformation being outputted from the known sequence detector 2004.Namely, the 1^(st) known sequence (or training sequence) is located atthe last 2 segments of the 3^(rd) M/H block (B3) within the data group.The 2^(nd) training sequence may be inserted at the 2^(nd) and 3^(rd)segments of the 4^(th) M/H block (B4). The 2^(nd) known sequence islocated at between 2^(nd) and 3^(rd) segments of the 4^(th) M/H block(B4) within the data group. Since the 2^(nd) known sequence is insertedand received next to the signaling information area, the signalingdecoder 2013 may extract and decode signaling information included inthe signaling information region from the data being outputted in thedemodulator 2002 or the channel equalizer 2003.

The power controller 5000 is inputted the M/H frame-associatedinformation from the signaling decoder 2013, and controls power of thetuner and the demodulating unit. Alternatively, the power controller5000 is inputted a power control information from the operationcontroller 2000, and controls power of the tuner and the demodulatingunit.

According to the embodiment of the present invention, the powercontroller 5000 turns the power on only during a slot to which a slot ofthe parade including user-selected mobile service is assigned. The powercontroller 5000 then turns the power off during the remaining slots.

For example, it is assumed that data groups of a 1^(st) parade withNOG=3, a 2^(nd) parade with NOG=2, and a 3^(rd) parade with NOG=3 areassigned to one M/H frame, as shown in FIG. 37. It is also assumed thatthe user has selected a mobile service included in the 1^(st) paradeusing the keypad provided on the remote controller or terminal. In thiscase, the power controller 5000 turns the power on during a slot thatdata groups of the 1^(st) parade is assigned, as shown in FIG. 37, andturns the power off during the remaining slots, thereby reducing powerconsumption.

The demodulator 2002 uses the known data symbol sequence during thetiming and/or carrier recovery, thereby enhancing the demodulatingperformance. Similarly, the equalizer 2003 uses the known data so as toenhance the equalizing performance. Moreover, the decoding result of theblock decoder 2005 may be fed-back to the equalizer 2003, therebyenhancing the equalizing performance.

Demodulator and Known Sequence Detector

At this point, the transmitting system may receive a data frame (or VSBframe) including a data group which known data sequence (or trainingsequence) is periodically inserted therein, as shown in FIG. 5. Herein,the data group is divided into regions A to D, as shown in FIG. 5. Morespecifically, in the example of the present invention, each region A, B,C, and D are further divided into M/H blocks B4 to B7, M/H blocks B3 andB8, M/H blocks B2 and B9, M/H blocks B1 and B10, respectively.

Referring to FIG. 38 and FIG. 39, known data sequence having the samepattern are included in each known data section that is beingperiodically inserted. Herein, the length of the known data sequencehaving identical data patterns may be either equal to or different fromthe length of the entire (or total) known data sequence of thecorresponding known data section (or block). If the two lengths aredifferent from one another, the length of the entire known data sequenceshould be longer than the length of the known data sequence havingidentical data patterns. In this case, the same known data sequences areincluded in the entire known data sequence.

As described above, when the known data are periodically insertedin-between the mobile service data, the channel equalizer of thereceiving system may use the known data as training sequences, which maybe used as accurate discriminant values. According to another embodimentof the present invention, the channel equalizer estimates a channelimpulse response. Herein, the known data may be used in the process.According to yet another embodiment of the present invention, thechannel equalizer may use the known data for updating filtercoefficients (i.e., equalization coefficients).

Meanwhile, when known data sequence having the same pattern isperiodically inserted, each known data sequence may be used as a guardinterval in a channel equalizer according to the present invention.Herein, the guard interval prevents interference that occurs betweenblocks due to a multiple path channel. This is because the known datasequence located behind a mobile service data section (i.e., data block)may be considered as being copied in front of the mobile service datasection.

The above-described structure is referred to as a cyclic prefix. Thisstructure provides circular convolution in a time domain between a datablock transmitted from the transmitting system and a channel impulseresponse. Accordingly, this facilitates the channel equalizer of thereceiving system to perform channel equalization in a frequency domainby using a fast fourier transform (FFT) and an inverse fast fouriertransform (IFFT).

More specifically, when viewed in the frequency domain, the data blockreceived by the receiving system is expressed as a multiplication of thedata block and the channel impulse response. Therefore, when performingthe channel equalization, by multiplying the inverse of the channel inthe frequency domain, the channel equalization may be performed moreeasily.

The known sequence detector 2004 detects the position of the known databeing periodically inserted and transmitted as described above. At thesame time, the known sequence detector 2004 may also estimate initialfrequency offset during the process of detecting known data. In thiscase, the demodulator 2002 may estimate with more accuracy carrierfrequency offset from the information on the known data positioninformation and initial frequency offset estimation value, therebycompensating the estimated carrier frequency offset.

Meanwhile, when known data is transmitted, as shown in FIG. 5, the knownsequence detector 2004 detects a position of second known data region byusing known data of the second known data region that the same patternis repeated twice.

At this point, since the known sequence detector 2004 is well-informedof the data group structure, when the position of the second known dataregion is detected, the known sequence detector 2004 can estimatepositions of the first, third, fourth, fifth, and sixth known dataregions of a corresponding data group by counting symbols or segmentsbased upon the second known data region position. If the correspondingdata group is a data group including field synchronization segment, theknown sequence detector 2004 can estimate the position of the fieldsynchronization segment of the corresponding data group, which ispositioned chronologically before the second known data region, bycounting symbols or segments based upon the second known data regionposition. Also, the known sequence detector 2004 may estimate the knowndata position information and the field synchronization positioninformation from the parade including mobile service selected by a userbased on the M/H frame-associated information outputted from thesignaling decoder 2013.

At least one of the estimated known data poison information and fieldsynchronization information is provided to the demodulator 2002, thechannel equalizer 2003, the signaling decoder 2013, and the operationcontroller 2000.

Also, the known sequence detector 2004 may estimate initial frequencyoffset by using known data inserted in the second known data region(i.e., ACQ known data region). In this case, the demodulator 2002 mayestimate with more accuracy carrier frequency offset from theinformation on the known data position information and initial frequencyoffset estimation value, thereby compensating the estimated carrierfrequency offset.

Operation Controller

The operation controller 2000 receives the known data positioninformation and the transmission parameter information and then forwardsM/H frame time information, a presence or non-presence of a data groupof a selected parade, position information of known data within the datagroup, power control information and the like to each block of thedemodulating unit. The operation controller 2000, as shown in FIG. 41,controls operations of the demodulator 2002, the channel equalizer 2003,the block decoder 2005 and the RS frame decoder 2006. And, the operationcontroller 2000 is able to overall operations of the demodulating unit(not shown in the drawing). Moreover, the operation controller 2000 canbe implemented with the separate block or can be included within aprescribed one of the blocks of the demodulating unit shown in FIG. 41.

FIG. 42 is an overall block diagram of an operation controller 2000.

Referring to FIG. 42, the operation controller 2000 can include a paradeID checker 3101, a frame synchronizer 3102, a parade mapper 3103, agroup controller 3104 and a known sequence indication controller 3105.

The operation controller 2000 receives known data position informationfrom the known sequence detector 2004 and receives transmissionparameter information from the signaling decoder 2013. The operationcontroller 2000 then generates a control signal necessary for ademodulating unit of a receiving system. For instance, the known dataposition information detected by the known sequence detector 2004 isinputted to the known sequence indication controller 3105. And, thetransmission parameter information (i.e., TPC data) decoded by thesignaling decoder 2013 is inputted to the parade ID checker 3101.

The parade ID checker 3101 compares a parade ID (parade ID selected by auser) contained in the user control signal to a parade ID inputted fromthe signaling decoder 2013. If the two parade IDs are not identical toeach other, the parade ID checker stands by until a next transmissionparameter is inputted from the signaling decoder 2013.

If the two parade IDs are identical to each other, the parade ID checker3101 outputs the transmission parameter information to the blocks withinthe operation controller 2000 and the overall system.

If it is checked that the parade ID in the transmission parameterinformation inputted to the parade ID checker 3101 is identical to theparade ID selected by a user, the parade ID checker 3101 outputsstarting_group_number (SGN) and number_of_groups (NOG) to the parademapper 3103, outputs sub_frame_number, slot_number andparade_repetition_cycle PRC) to the frame synchronizer 3102, outputsSCCC_block_mode, SCCC_outer_code_mode_A, SCCC_outer_code_mode_B,SCCC_outer_code_mode_C and SCCC_outer_code_mode_D to the block decoder2005, and outputs RS_frame_mode, RS_code_mode_primary andRs_code_mode_secondary to the RS frame decoder 2006.

The parade mapper 3103 receives the SGN and the NOG from the parade IDchecker as inputs, decides a data group is carried by which one ofsixteen slots within a Sub-frame, and then outputs the correspondinginformation. Data group number transmitted every sub-frame is set to aninteger consecutive between SGN and (SGN+NOG−1). For instance, if SGN=3and NOG=4, four groups, of which group numbers are 3, 4, 5 and 6, aretransmitted for the corresponding sub-frames, respectively. The parademapper finds a slot number j for transmitting a data group according toEquation 1 with a group number i obtained from SGN and NOG.

In the above example, in case of SGN=3 and NOG=4, if they are insertedin Equation 1, slot numbers of groups transmitted according to the aboveformula sequentially become 12, 2, 6 and 10.

The parade mapper 3103 then outputs the found slot number information.

For example of outputting slot numbers, a method of using a bit vectorhaving 16 bits is available.

A bit vector SNi (i=0˜15) can be set to 1 if there exists a grouptransmitted for an i^(th) slot. A bit vector SNi (i=0˜15) can be set to0 if a group transmitted for an i^(th) slot does not exist. And, thisbit vector can be outputted as slot number information.

The frame synchronizer 3102 receives the sub_frame_number, slot-numberand PRC from the parade ID checker and then sends slot_counter andframe_mask signals as outputs. The slot_counter is the signal indicatinga slot_number at a current timing point at which a receiver isoperating. And, the frame_mask is the signal indicating whether acorresponding parade is transmitted for a current frame. The framesynchronizer 3102 performs a process for initializing slot_counter,sub_frame_number and frame_counter in receiving signaling informationinitially. A counter value of a current timing point is generated fromadding a delayed slot number L according to a time taken to decodesignaling from demodulation together with the signaling informationinputted in this process. After completion of the initializationprocess, slot_counter is updated every single slot period, updatessub_frame_counter every period of the slot_counter value, and updatesframe_counter every period of the sub_frame_counter. By referring to theframe_counter information and the PRC information, a frame_mask signalis generated. For example, if a corresponding parade is beingtransmitted for a current frame, ‘1’ is outputted as the frame_mask.Otherwise, it is able to output ‘0’.

The group controller 3104 receives the slot number information from theparade mapper 3103. The group controller 3104 receives the slot_counterand frame_mask information from the frame synchronizer 3102. The groupcontroller 3104 then outputs group_presence_indicator indicating whetheran M/H group is being transmitted. For instance, if the slot numberinformation inputted from the parade mapper 3103 corresponds to 12, 2, 6and 10, when the frame_mask information inputted from the framesynchronizer 3102 is 1 and the slot_counter inputted from the framesynchronizer 3102 includes 2, 6, 10 and 12, ‘1’ is outputted as thegroup_presence_indicator. Otherwise, it is able to output 0.

The known sequence indication controller 3105 outputs positioninformation of another known data, group start position information andthe like with position information of specific inputted known data. Inthis case, since the known data are present at a previously appointedposition within the data group, if position data of one of a pluralityof known data sequences, it is able to know data position information ofanother known sequence, data group start position information and thelike. The known sequence indication controller 3105 can output knowndata and data group position information necessary for the demodulatingunit of the receiving system using the group_presence_indicatorinformation only if the data group is transmitted. Alternatively, theknown sequence detector 2004 can perform operations of the knownsequence indication controller 3105.

Channel Equalizer

The data demodulated by the demodulator 2002 by using the known data areinputted to the equalizer 2003. Additionally, the demodulated data mayalso be inputted to the known sequence detector 2004.

At this point, a data group that is inputted for the equalizationprocess may be divided into region A to region D, as shown in FIG. 5.More specifically, according to the embodiment of the present invention,region A includes M/H block B4 to M/H block B7, region B includes M/Hblock B3 and M/H block B8, region C includes M/H block B2 and M/H blockB9, and region D includes M/H block B1 and M/H block B10. In otherwords, one data group is divided into M/H blocks from B1 to B10, eachM/H block having the length of 16 segments. Also, a long trainingsequence (i.e., known data sequence) is inserted at the starting portionof the M/H blocks B4 to B8. Furthermore, two data groups may beallocated (or assigned) to one VSB field. In this case, fieldsynchronization data are positioned in the 37^(th) segment of one of thetwo data groups.

Therefore, in a data group including field synchronization data, whencounting each segment starting from the first segment including mobileservice data, which is counted as segment number 0 (#0), fieldsynchronization is located in a position corresponding to segment number37 (#37). Thereafter, 5 known data sequences are respectively located inpositions corresponding to each of segment number (#53), segment number69 (#69), segment number 85 (#85), segment number 101 (#101), andsegment number 117 (#117). More specifically, a 1^(st) known datasequence is located in segment number 53 (#53), a 3^(rd) known datasequence is located in segment number 69 (#69), a 4^(th) known datasequence is located in segment number 85 (#85), a 5^(th) known datasequence is located in segment number 101 (#101), and a 6^(th) knowndata sequence is located in segment number 117 (#117).

The present invention may use known data and/or field synchronizationdata for performing channel-equalization, wherein the positions andcontents of the known data and/or field synchronization data are knownbased upon an agreement between the transmitting system and thereceiving system.

According to an embodiment of the present invention, the presentinvention may enhance the receiving performance of the presentinvention, by using the known data and/or field synchronization data soas to estimate a channel impulse response (CIR), and by compensatingdistortions, i.e., performing channel-equalization using the estimatedCIR.

In the description of the present invention, at least one of a knowndata sequence and a field synchronization data sequence will be referredto as a training sequence. More specifically, in a data group includingfield synchronization data, a field synchronization data sequence and aknown data sequence correspond to the training sequence. However, in adata group that does not include any field synchronization data, onlythe known data sequence corresponds to the training sequence.Furthermore, at least one of a known data section and a fieldsynchronization section will be referred to as a training section.

In the training section, the present invention uses a training sequenceto estimate a CIR and, then, uses the estimated CIR to channel-equalizethe training sequence. Also, in a non-training section, i.e., in ageneral data section, the present invention interpolates or extrapolatesusing the CIRs estimated in the training section and, then, uses the CIRgenerated by interpolation or extrapolation, so as to channel-equalizethe general data. According to the embodiment of the present invention,the general data correspond to mobile service data.

FIG. 44 illustrates the relation between a segment and a channel impulseresponse (CIR) in a data group including field synchronization dataaccording to the present invention. And, FIG. 45 illustrates therelation between a segment and a channel impulse response (CIR) in adata group not including any field synchronization data according to thepresent invention.

Hereinafter, the CIR estimated in the field synchronization section willbe referred to as CIR(37), the CIR estimated in the 1^(st) known datasequence section will be referred to as CIR(53), the CIR estimated inthe 3^(rd) known data sequence section will be referred to as CIR(69),the CIR estimated in the 4^(th) known data sequence section will bereferred to as CIR(85), the CIR estimated in the 5^(th) known datasequence section will be referred to as CIR(101), and the CIR estimatedin the 6^(th) known data sequence section will be referred to asCIR(117), for simplicity.

More specifically, the present invention uses the CIR estimated in theknown data section and/or field synchronization section so as to performchannel-equalization on the data within the respective data group. Atthis point, depending upon the characteristics of each region of thedata group, any one of the estimated CIRs may be directly used withoutmodification, or a CIR generated by interpolating or extrapolating atleast 2 or more CIRs may be used.

Herein, when a value F(Q) of a function F(x) at a particular point Q anda value F(S) of the function F(x) at another particular point S areknown, interpolation refers to estimating a function value of a pointwithin the section between points Q and S.

In the description of the present invention, a linear interpolationmethod will be described according to a first embodiment of the presentinvention, and a cubic spline interpolation method will be describedaccording to a second embodiment of the present invention.

First Embodiment

FIG. 43 illustrates an example of linear interpolation according to thepresent invention. More specifically, in a random function F(x), whengiven the values F(Q) and F(S) each from points x=Q and x=S,respectively, the approximate value {circumflex over (F)}^((P)) of theF(x) function at point x=P may be estimated by using Equation 7 below.In other words, since the values of F(Q) and F(S) respective to eachpoint x=Q and x=S are known (or given), a straight line passing throughthe two points may be calculated so as to obtain the approximate value{circumflex over (F)}^((P)) of the corresponding function value at pointP. At this point, the straight line passing through points (Q,F(Q)) and(S,F(S)) may be obtained by using Equation 7 below.

$\begin{matrix}{{\hat{F}(x)} = {{\frac{{F(S)} - {F(Q)}}{S - Q}\left( {x - Q} \right)} + {F(Q)}}} & {{Equation}\mspace{14mu} 7}\end{matrix}$

Accordingly, Equation 8 below shows the process of substituting p for xin Equation 7, so as to calculate the approximate value {circumflex over(F)}^((P)) of the function value at point P.

$\begin{matrix}{{{\hat{F}(P)} = {{\frac{{F(S)} - {F(Q)}}{S - Q}\left( {P - Q} \right)} + {F(Q)}}}{{\hat{F}(P)} = {{\frac{S - P}{S - Q}{F(Q)}} + {\frac{P - Q}{S - Q}{F(S)}}}}} & {{Equation}\mspace{14mu} 8}\end{matrix}$

In FIG. 44 and FIG. 45, when calculating the CIR of a general datasection, i.e., section [a] to section [e], and not of a training sectionusing linear interpolation, the CIR may be calculated by using Equation8 shown above.

For example, the CIR of section [a] may be obtained by respectivelysubstituting CIR(37) and CIR(53) for F(Q) and F(S) of Equation 8, andthe CIR of section [b] may be obtained by respectively substitutingCIR(53) and CIR(69) for F(Q) and F(S) of Equation 8. Similarly, the CIRof section [c] may be obtained by respectively substituting CIR(69) andCIR(85) for F(Q) and F(S) of Equation 8. The CIR of section [d] may beobtained by respectively substituting CIR(85) and CIR(101) for F(Q) andF(S) of Equation 8. And, finally, the CIR of section [e] may be obtainedby respectively substituting CIR(101) and CIR(117) for F(Q) and F(S) ofEquation 8. Thereafter, the CIRs obtained in each section are used tochannel-equalize the data of the respective section. For example, theCIR obtained in section [a] using linear interpolation is used forchannel-equalizing the mobile service data of section [a].

Second Embodiment

Meanwhile, in FIG. 44 and FIG. 45, the CIR of a general data section,i.e., section [a] to section [e], and not of a training section usinglinear interpolation, may be calculated by using another interpolationmethod.

According to a second embodiment of the present invention, the CIR ofsection [a] to section [e] may be calculated by using a cubic splineinterpolation method.

The cubic spline interpolation method uses a cubic equation, as shown inEquation 9 below.fi(x)=ai*x ³ +bi*x ² +ci*x+di  Equation 9

The cubic (polynomial) equation that can be in natural (or easy)connection with other polynomial equations of earlier or later sectionsis selected as the cubic equation. The functions selected in eachsection will be referred to as a cubic spline interpolation function, ora spline interpolation function, or a cubic function, or a function.When selecting the spline interpolation function in each section, thespline interpolation functions before and after each point should beable to be processed with and each function should have the samecurvature.

More specifically, when generating a CIR of a particular section usingcubic spline interpolation, all possible CIRs are used, instead of usingonly the two most approximate CIRs, as in the linear interpolationmethod.

According to the embodiment of the present invention, in the data groupthat does not include field synchronization data, the present inventionmay use 5 CIRs, i.e., CIR(53), CIR(69), CIR(85), CIR(101), and CIR(117),so as to generate cubic polynomial equations of section [b] to section[e] (i.e., 4 sections). And, in the data group that includes fieldsynchronization data, the present invention may use 6 CIRs, i.e.,CIR(37), CIR(53), CIR(69), CIR(85), CIR(101), and CIR(117), so as togenerate cubic polynomial equations of section [a] to section [e] (i.e.,5 sections). At this point, the cubic equation, i.e., splineinterpolation function, applied to each section is different from oneanother. In other words, the coefficient of the cubic equation appliedto each section is different from one another.

For example, the cubic equation, i.e., cubic interpolation function, forcalculating the CIR of section [a] using cubic spline interpolation isshown in Equation 10 below.f0(x)=a0*x ³ +b0*x ² +c0*x+d0  Equation 10

The cubic equation for calculating the CIR of section [b] is shown inEquation 11 below.f1(x)=a1*x ³ +b1*x ² +c1*x+d1  Equation 11

The cubic equation for calculating the CIR of section [c] is shown inEquation 12 below.f2(x)=a2*x ³ +b2*x ² +c2*x+d2  Equation 12

The cubic equation for calculating the CIR of section [d] is shown inEquation 13 below.f3(x)=a3*x ³ +b3*x ² +c3*x+d3  Equation 13

The cubic equation for calculating the CIR of section [e] is shown inEquation 14 below.f4(x)=a4*x ³ +b4*x ² +c4*x+d4  Equation 14

Herein, the CIR calculated in the field synchronization section, i.e.,CIR(37), will be referred to as f(0), the CIR obtained in the 1^(st)known data sequence, i.e., CIR(53), will be referred to as f(1), the CIRobtained in the 3^(rd) known data sequence, i.e., CIR(69), will bereferred to as f(2), the CIR obtained in the 4^(th) known data sequence,i.e., CIR(85), will be referred to as f(3), the CIR obtained in the5^(th) known data sequence, i.e., CIR(101), will be referred to as f(4),and the CIR obtained in the 6^(th) known data sequence, i.e., CIR(117),will be referred to as f(5), for simplicity.

At this point, Equation 15 shown below corresponds to a matrix used forcalculating the coefficient of each cubic equation in the data groupthat does not include field synchronization data. And, Equation 16 shownbelow corresponds to a matrix used for calculating the coefficient ofeach cubic equation in the data group including field synchronizationdata.

$\begin{matrix}{\begin{matrix}{a\; 1} \\{b\; 1} \\{c\; 1} \\{d\; 1} \\{a\; 2} \\{b\; 2} \\{c\; 2} \\{d\; 2} \\{a\; 3} \\{b\; 3} \\{c\; 3} \\{d\; 3} \\{a\; 4} \\{b\; 4} \\{c\; 4} \\{d\; 4}\end{matrix} = {\frac{1}{56}\begin{matrix}15 & {- 34} & 24 & {- 6} & 1 \\{- 45} & 102 & {- 72} & 18 & {- 3} \\{- 26} & {- 12} & 48 & {- 12} & 2 \\112 & {- 56} & {{0.00E} + 00} & {{0.00E} + 00} & {{0.00E} + 00} \\{- 19} & 58 & {- 64} & 30 & {- 5} \\159 & {- 450} & 456 & {- 198} & 33 \\{- 434} & 1092 & {- 1008} & 420 & {- 70} \\384 & {- 792} & 704 & {- 288} & 48 \\5 & {- 30} & 64 & {- 58} & 19 \\{- 57} & 342 & {- 696} & 594 & {- 183} \\214 & {- 1284} & 2448 & {- 1956} & 578 \\{- 264} & 1584 & {- 2752} & 2088 & {- 600} \\{- 1} & 6 & {- 24} & 34 & {- 15} \\15 & {- 90} & 360 & {- 510} & 225 \\{- 74} & 444 & {- 1776} & 2460 & {- 1054} \\120 & {- 720} & 2880 & {- 3800} & 1576\end{matrix}*\begin{matrix}{f(1)} \\{f(2)} \\{f(3)} \\{f(4)} \\{f(5)}\end{matrix}}} & {{Equation}\mspace{14mu} 15} \\{\begin{matrix}{a\; 0} \\{b\; 0} \\{c\; 0} \\{d\; 0} \\{a\; 1} \\{b\; 1} \\{c\; 1} \\{d\; 1} \\{a\; 2} \\{b\; 2} \\{c\; 2} \\{d\; 2} \\{a\; 4} \\{b\; 4} \\{c\; 4} \\{d\; 4} \\{a\; 5} \\{b\; 5} \\{c\; 5} \\{d\; 5}\end{matrix} = {\frac{1}{209}\begin{matrix}56 & {- 127} & 90 & {- 24} & 6 & {- 1} \\0 & 0 & 0 & 0 & 0 & 0 \\{- 265} & 336 & {- 90} & 24 & {- 6} & 1 \\209 & 0 & 0 & 0 & 0 & 0 \\{- 71} & 217 & {- 241} & 120 & {- 30} & 5 \\381 & {- 1032} & 993 & {- 432} & 108 & {- 18} \\{- 646} & 1368 & {- 1083} & 456 & {- 114} & 19 \\336 & {- 344} & 331 & {- 144} & 36 & {- 6} \\19 & {- 114} & 247 & {- 247} & 114 & {- 19} \\{- 159} & 954 & {- 1935} & 1770 & {- 756} & 126 \\434 & {- 2604} & 4773 & {- 3948} & 1614 & {- 269} \\{- 384} & 2304 & {- 3573} & 2792 & {- 1116} & 186 \\{- 5} & 30 & {- 120} & 241 & {- 217} & 71 \\57 & {- 342} & 1368 & {- 2622} & 2223 & {- 684} \\{- 214} & 1284 & {- 5136} & 9228 & {- 7323} & 2161 \\264 & {- 1584} & 6336 & {- 10384} & 7821 & {- 2244} \\1 & {- 6} & 24 & {- 90} & 127 & {- 56} \\{- 15} & 90 & {- 360} & 1350 & {- 1905} & 840 \\74 & {- 444} & 1776 & {- 6660} & 9189 & {- 3935} \\{- 120} & 720 & {- 2880} & 10800 & {- 14195} & 5884\end{matrix}*\begin{matrix}{f(0)} \\{f(1)} \\{f(2)} \\{f(3)} \\{f(4)} \\{f(5)}\end{matrix}}} & {{Equation}\mspace{14mu} 16}\end{matrix}$

More specifically, Equation 15 corresponds to an equation used forcalculating coefficients (a1 to d4) of cubic equations (f1(x), f2(x),f3(x), and f4(x)) corresponding to 4 different sections. The constantmatrix in Equation 15 has the size of [16×5], and the CIR matrix has thesize of [5×1].

Alternatively, Equation 16 corresponds to an equation used forcalculating coefficients (a0 to d4) of cubic equations (f0(x), f1(x),f2(x), f3(x), and f4(x)) corresponding to 5 different sections. Theconstant matrix in Equation 16 has the size of [20×6], and the CIRmatrix has the size of [6×1].

In Equation 15 and Equation 16, the constant matrix by which each CIR ismultiplied corresponds to a pre-decided value stored in the memory. Thisvalue may be decided through experiments or may be decided bycalculation using calculating tools. Also, the constant matrix may bestored in the memory in the form of a look-up table. The value of theconstant matrix is influenced by the number of points that are to bereferred to, i.e., by the number of CIRs. Moreover, the value of theconstant matrix is also influenced by the x value. For example, thevalue of the constant matrix varies when x=0, 1, 2, 3, . . . , as shownin FIG. 44 and FIG. 45 and when x=16, 32, 48, . . . .

When calculating coefficients (a1 to d1) of the cubic equation insection [b] corresponding to the data group that does not include fieldsynchronization data by applying Equation 15, the coefficients may becalculated as shown in Equation 17 below.a1=15/56*f(1)−34/56*f(2)+24/56*f(3)−6/56*f(4)+1/56b1=−45/56*f(1)+102/56*f(2)−72/56*f(3)+18/56*f(4)−3/56c1=−26/56*f(1)−12/56*f(2)+48/56*f(3)−12/56*f(4)+2/56d1=112/56*f(1)−56/56*f(2)  Equation 17

In Equation 17, f(1) to f(5) respectively correspond to CIR valuesestimated by using the 1^(st) known data sequence, and the 3^(rd) to6^(th) known data sequences. Therefore, the coefficients obtained inEquation 17 are applied to the cubic equation shown in Equation 11.Then, when a specific point, i.e., x value, within section [b] issubstituted by the coefficients, the CIR value of the pointcorresponding to the x value may be calculated.

As described above, when generating a CIR for each section using cubicspline interpolation, so as to channel-equalize data of thecorresponding section, the present invention may perform enhancedchannel-equalization, as compared to when using linear interpolation.However, in order to enhance channel-equalizing performance using cubicspline interpolation, the structure and design of the present inventionwill become more complicated. For example, when calculating the CIRusing linear interpolation, a memory capacity (or size) for storing thedata of one section (e.g., in the present invention, one sectioncorresponds to the size of 16 segments) is required. This is because theknown data sequence corresponding to the 53^(rd) segment is required forcompensating channel distortion in the first data set of section [a].

Conversely, when calculating the CIR using cubic spline interpolation,data corresponding to up to the 117^(th) segment are required forcompensating channel distortion in the first data set of section [a].Therefore, a memory size capable of storing all data corresponding tothe 5 sections is required. Arithmetically, the cubic splineinterpolation method requires a memory size 5 times the size of a memoryused in the linear interpolation method. Therefore, by considering theequalizing performance, price, complexity, and so on, the presentinvention uses one of linear interpolation and cubic splineinterpolation, so as to generate a CIR of a general data section locatedbetween training sections.

Meanwhile, as described above, when using the cubic spline interpolationmethod, in the data group that does not include field synchronizationdata, 5 CIRs, i.e., CIR(53), CIR(69), CIR(85), CIR(101), and CIR(117),are applied to the matrix shown in Equation 15, thereby obtainingcoefficients of cubic equations corresponding to 4 sections.Additionally, in the data group including field synchronization data, 6CIRs, i.e., CIR(37), CIR(53), CIR(69), CIR(85), CIR(101), and CIR(117),are applied to the matrix shown in Equation 16, thereby obtainingcoefficients of cubic equations corresponding to 5 sections.

However, as shown in FIG. 44 and FIG. 45, although each of section [b],section [c], section [d], and section [e] corresponds to the samesection within the data group regardless of the field synchronizationdata, the constants being multiplied by each CIR in the actualpolynomial equation are different from one another, as shown in Equation15 and Equation 16.

For example, in Equation 15, which is applied when using a data groupthat does not include the field synchronization data, the constantmultiplied by each CIR in order to calculate coefficient a1 of section[b] corresponds to 1/56[15−34 24−6 1]. On the other hand, in Equation16, which is applied when using a data group including the fieldsynchronization data, the constant multiplied by each CIR in order tocalculate coefficient a1 of section [b] corresponds to 1/209[−71 217−241120−30 6].

As described above, although each of section [b], section [c], section[d], and section [e] corresponds to the same section within the datagroup regardless of the field synchronization data, in theabove-described embodiment, since a different constant is applieddepending upon the presence or absence of the field synchronizationdata, the complexity of the present invention may be increased. Morespecifically, although section [b], section [c], section [d], andsection [e] are located in the same position within all data groups,different cubic equations should be devised depending upon the presenceor absence of the field synchronization data. Therefore, the complexityof the present invention is eventually increased.

According to another embodiment of the present invention, the same cubicequations are applied to the sections located in the same position foreach data group, so as to simplify the system complexity. Then, by usingthe cubic spline interpolation method, the increasing memory capacitymay also be reduced. For this, the present invention uses the same cubicequation to calculate the CIR of a general data section located betweentraining sections in all data groups, regardless of the presence orabsence of the field synchronization data. More specifically, regardlessof the presence or absence of the field synchronization data, thecoefficients of each cubic equation of respective general data sectionslocated between training sections within each data group are calculatedby applying a single constant matrix.

For example, the present invention uses 5 CIRs to generate the cubicequation of the general data section located between training sectionsin all data groups, regardless of the presence or absence of the fieldsynchronization data. However, this is merely exemplary. Therefore, inother examples, 4 CIRs may be used or 3 CIRs may be used to generate thecorresponding cubic equation. More specifically, the present inventionuses the same number of CIRs, i.e., the same number of observationpoints, so as to configure the cubic equation of the general datasection located between training sections in all data groups, regardlessof the presence or absence of the field synchronization data.

Furthermore, regardless of the presence or absence of the fieldsynchronization data, the present invention uses the constant matrix ofEquation 15 so as to calculate the coefficients of the cubic equation.

More specifically, 5 points (i.e., 5 CIRs) are used to respectivelygenerate the cubic equations (f0(x) to f4(x)) for section [a] to section[e] of the data group including the field synchronization data. And, 5points (i.e., 5 CIRs) are also used to respectively generate the cubicequations (f1(x) to f4(x)) for section [b] to section [e] of the datagroup that does not include any field synchronization data. Moreover,regardless of the presence or absence of the field synchronization data,the constant matrix of Equation 15 is used as the constants, which aremultiplied by the 5 CIRs so as to calculate the coefficients of thecubic equations (f0(x) to f4(x)) for section [a] to section [e] or thecubic equations (f1(x) to f4 (x)) for section [b] to section [e].Accordingly, since the constant matrix of Equation 16 is no longerrequired to be stored, the memory capacity can be reduced.

At this point, the 5 CIRs of the training sections that are used tocalculate the CIR of section [b] to section [e] of the data group thatdoes not include any field synchronization data respectively correspondto CIR(53) (=f(1)), CIR(69) (=f(2)), CIR(85) (=f(3)), CIR(101) (=f(4)),and CIR(117)(=f(5)). More specifically, the CIR applied to the matrix ofEquation 15 corresponds to f(1) to f(5), the description of which isidentical the above-described method.

However, in the data group including the field synchronization data, the5 CIRs applied to each section vary.

For example, the 5 CIRs of the training section used for calculating theCIR of section [a] in the data group including the field synchronizationdata, respectively correspond to CIR(37) (=f(0)), CIR(53) (=f(1)),CIR(69) (=f(2)), CIR(85) (=f(3)), and CIR(101) (=f(4)). Morespecifically, the CIRs applied to the matrix of Equation 15 correspondto f(0) to f(4). Also, the 5 CIRs of the training section used forcalculating the CIRs of section [b] to section [d] in the data groupincluding the field synchronization data, may respectively correspond toCIR(37)(=f(0)), CIR(53) (=f(1)), CIR(69) (=f(2)), CIR(85) (=f(3)), andCIR(101) (=f(4)), or may respectively correspond to CIR(53) (=f(1)),CIR(69) (=f(2)), CIR(85) (=f(3)), CIR(101) (=f(4)), and CIR(117)(=f(5)). More specifically, the CIRs applied to the matrix of Equation15 may correspond to f(0) to f(4), or the CIRs applied to the matrix ofEquation 15 may correspond to f(1) to f(5).

Furthermore, the 5 CIRs of the training section used for calculating theCIR of section [e] in the data group including the field synchronizationdata, respectively correspond to CIR(53) (=f(1)), CIR(69) (=f(2)),CIR(85) (=f(3)), CIR(101) (=f(4)), and CIR(117) (=f(5)). Morespecifically, the CIRs applied to the matrix of Equation 15 correspondto f(1) to f(5).

Equation 18 shown below corresponds to a matrix used for calculating thecoefficient of a cubic equation in each section by applying f(0) to f(4)to the constant matrix of Equation 15 in the data group including thefield synchronization data.

$\begin{matrix}{\begin{matrix}{a\; 0} \\{b\; 0} \\{c\; 0} \\{d\; 0} \\{a\; 1} \\{b\; 1} \\{c\; 1} \\{d\; 1} \\{a\; 2} \\{b\; 2} \\{c\; 2} \\{d\; 2} \\{a\; 3} \\{b\; 3} \\{c\; 3} \\{d\; 3}\end{matrix} = {\frac{1}{56}\begin{matrix}15 & {- 34} & 24 & {- 6} & 1 \\{- 45} & 102 & {- 72} & 18 & {- 3} \\{- 26} & {- 12} & 48 & {- 12} & 2 \\112 & {- 56} & {{0.00E} + 00} & {{0.00E} + 00} & {{0.00E} + 00} \\{- 19} & 58 & {- 64} & 30 & {- 5} \\159 & {- 450} & 456 & {- 198} & 33 \\{- 434} & 1092 & {- 1008} & 420 & {- 70} \\384 & {- 792} & 704 & {- 288} & 48 \\5 & {- 30} & 64 & {- 58} & 19 \\{- 57} & 342 & {- 696} & 594 & {- 183} \\214 & {- 1284} & 2448 & {- 1956} & 578 \\{- 264} & 1584 & {- 2752} & 2088 & {- 600} \\{- 1} & 6 & {- 24} & 34 & {- 15} \\15 & {- 90} & 360 & {- 510} & 225 \\{- 74} & 444 & {- 1776} & 2460 & {- 1054} \\120 & {- 720} & 2880 & {- 3800} & 1576\end{matrix}*\begin{matrix}{f(0)} \\{f(1)} \\{f(2)} \\{f(3)} \\{f(4)}\end{matrix}}} & {{Equation}\mspace{14mu} 18}\end{matrix}$

As shown in Equation 15, the constant matrix in Equation 18 also has thesize of [16×5], and the CIR matrix also has the size of [5×1]. Morespecifically, the constant matrix of Equation 15 and that of Equation 18are identical to one another.

However, one of the characteristics of the cubic spline interpolationmethod is that, since there is no extending information at the far-endside, the performance at the far-end section may be deteriorated ascompared to the inner sections.

More specifically, when comparing Equation 15 with Equation 18, inEquation 15, the coefficients of section [b] and section [e], a1 to d1and a4 to d4 correspond to the information of the far-end section. And,in Equation 18, the coefficients of section [a] and section [d], a0 tod0 and a3 to d3 correspond to the information of the far-end section.

At this point, since a0 to d0 and a4 to d4 do not overlap in Equation 15and Equation 18, the coefficients a0 to d0 of section [a] are calculatedby applying Equation 18, and the coefficients a4 to d4 of section [e]are calculated by applying Equation 15.

Furthermore, a1 to d1, a2 to d2, and a3 to d3 overlap in Equation 15 andEquation 18. At this point, in the cubic spline interpolation method,since there is no extending information at the far-end side, theperformance at the far-end section may be deteriorated as compared tothe inner sections. Therefore, according to the embodiment of thepresent invention, the coefficients a1 to d1 of section [b] arecalculated by applying Equation 18, which corresponds to the innersection, and the coefficients a3 to d3 of section [d] are calculated byapplying Equation 15, which corresponds to the inner section. And, sincethe coefficients a2 to d2 of section [c] correspond to the innersections in both Equation 15 and Equation 18, either one of Equation 15and Equation 18 may be used to calculate the coefficients a2 to d2.According to the embodiment of the present invention, the coefficientsa2 to d2 of section [c] are calculated by applying Equation 15.

In other words, in the data group including the field synchronizationdata, the present invention calculates coefficients a0 to d0 and a1 tod1 of section [a] and section [b] by applying Equation 18, and thepresent invention calculates coefficients a2 to d2, a3 to d3, and a4 tod4 of section [c] to section [e] by applying Equation 15. Thecoefficients calculated by using the above-described method aresubstituted in the cubic equations of section [a] to section [e] (i.e.,in f0(x), f1(x), f2(x), f3(x), and f4(x)), and when each of thecoefficients is substituted for a desired x value, CIRs of section [a]to section [e] may be generated by cubic spline interpolation.

Meanwhile, the constant matrix values of Equation 15 and Equation 18 areinfluenced by the x value. However, since the x values applied toEquation 15 (i.e., x=1 to 5) are different from the x values applied toEquation 18 (i.e., x=0 to 4), the constant matrix value of Equation 15and the constant matrix value of Equation 18 may actually vary. In otherwords, the constant matrix values used for calculating coefficients a0to d0 of section [a] and coefficients a1 to d1 of section [b] may differfrom the constant matrix values used for calculating coefficients a2 tod2 of section [c], coefficients a3 to d3 of section [d], andcoefficients a4 to d4 of section [e].

In order to resolve this problem, the x values of the cubic equation forsection [a] and section [b] may be substituted with x′ values, so as tocalculate the CIR of section [a] and the CIR of section [b]. In otherwords, by substituting x′ values for x values of a cubic function insections wherein i=0 and 1, the CIR of sections wherein i=0 and 1 may becalculated. However, in sections wherein i=2, 3, and 4 (i.e., in section[c] to section [e]), x values are substituted for the cubic function,thereby calculating the CIR.

Equation 19 below shows an example of a cubic equation (i.e., cubicfunction), which applies x′ values, so as to calculate CIRs of section[a] and section [b].f0(x′)=a0*x′ ³ +b0*x′ ² +c0*x′+d0f1(x′)=a1*x′ ³ +b1*x′ ² +c1*x′+d1  Equation 19

FIG. 46 illustrates an example for calculating the CIR of each sectionby substituting x′ values for the cubic functions in the sectionswherein i=0 and 1 (i.e., in section [a] and section [b]), and bysubstituting x values for the cubic functions in the sections whereini=2,3, and 4, within the data group including the field synchronizationdata. Herein, the x′ values may vary depending upon the x values of eachpoint. For example, when each point value corresponds to x=0, 1, 2, . .. , as shown in FIG. 44 and FIG. 45, then, x′=x+1. In another example,when each point value corresponds to x=16, 32, 48, . . . , then,x′=x+16. Such calculation is possible because in the present invention,a constant (or the same) interval between training sequences (e.g., 16segments) is maintained. More specifically, this is because the fieldsynchronization data sequence, the 1^(st) known data sequence, and the3^(rd) to 6^(th) known data sequences are spaced apart at intervals of16 segments. Thus, the design (or embodiment) of the receiving systemusing the cubic spline interpolation method may be simplified.

Meanwhile, when a value F(Q) of a function F(x) at a particular point Qand a value F(S) of the function F(x) at another particular point S areknown, extrapolation refers to estimating a function value of a pointoutside of the section between points Q and S. Herein, linearextrapolation is the simplest form among a wide range of extrapolationoperations.

FIG. 47 illustrates an example of linear extrapolation according to thepresent invention. As shown in the above-described example of linearinterpolation, in the linear extrapolation also, when using a randomfunction F(x), and when the values of F(Q) and F(S) respective to eachpoint x=Q and x=S are known (or given), a straight line passing throughthe two points may be calculated so as to obtain the approximate value{circumflex over (F)}^((P)) of the corresponding function value at pointP. Herein, linear extrapolation is one of the simplest examples among awide range of extrapolation methods. Accordingly, a variety ofextrapolation methods other than the above-described linearextrapolation method may be used. Therefore, the present invention willnot be limited only to the example given herein.

More specifically, in the data group including the field synchronizationdata, as shown in FIG. 44, the CIRs of section [f] and section [g] maybe calculated by extrapolating based upon 2 CIRs among CIR(37), CIR(53),CIR(69), CIR(85), CIR(101), and CIR(117). Alternatively, in the datagroup that does not include the field synchronization data, as shown inFIG. 45, the CIRs of section [h] and section [g] may be calculated byextrapolating based upon 2 CIRs among CIR(53), CIR(69), CIR(85),CIR(101), and CIR(117).

However, when CIR information can only be obtained from one direction,as in extrapolation, it is difficult to adequately compensate channeldistortion, as compared to the sections using interpolation. This isbecause there is an absolute lack of information on the respectivechannel at the point where the corresponding data experience distortion.

For example, it is assumed that in order to calculate the CIR of section[f], an equation for linear extrapolation is configured by using CIR(37)and CIR(53), and that the configured equation is extended and applied tosection [f]. In this case, as the CIR of the actual channel is spacedfurther apart from CIR(37), the difference between CIR(37) and the CIRcalculated in section [f] may become greater. Also, when configuring anequation for linear extrapolation by using CIR(37) and CIR(53), and whenthe configured equation is extended and applied to section [f], the CIRis extrapolated starting from the 37^(th) segment to the 0^(th) segment,and, as described above, the CIRs are extrapolated so as to compensatechannel distortion. Accordingly, problems of having the power of signalsafter compensation become higher or weaker may occur. In this case, inthe process for compensating channel distortion, the signal power may bedistorted, thereby becoming unable to provide optimum performance.

FIG. 48 illustrates an example of a signal power being distorted in aspecific segment (e.g., segment number (#10)) of section [f], whichcorresponds to one of the extrapolation sections of the data groupincluding the field synchronization data.

More specifically, although the signal power of the specific segment isin direct proportion to the power of CIR, the signal power in the10^(th) segment of the extrapolation section is higher, whereas the CIRpower is very weak (or low). In other words, in case of FIG. 48, the twopowers are not in direct proportion to one another. Therefore, in thepresent invention proposes a method for supplementing the problems ofexperiencing unintended signal power distortion.

For this, according to an embodiment of the present invention, thepresent invention compensates the power of the CIR estimated byextrapolation in the specific segment, so that the proportional relationbetween the power of the signal estimated from the specific segment ofthe extrapolation section and the power of the CIR generated byextrapolation can be identical to the proportional relation between thepower of the signal and the power of the CIR measured in the trainingsection. Accordingly, when adjusting the power of the CIR in theextrapolation section, as described above, the problems of unintendedincrease and/or decrease in signal power may be reduced.

In the present invention, the signal power may be calculated from asignal prior to being processed with channel-equalization, or from achannel-equalized signal. For example, the signal power may becalculated by squaring the input signal and accumulating the squaredvalue during a specific section (e.g., during the corresponding segmentsection). Also, the signal power may be measured via at least one ofsoftware and hardware.

Additionally, the method for compensating CIR power of an extrapolationsection may be applied section [f], section [g], and section [h] of FIG.44 and FIG. 45. According to an embodiment of the present invention,among the extrapolation sections, segment number 10 (#10) of section [f]will be described in detail.

More specifically, the CIR information acquired from fieldsynchronization data included in the 37^(th) segment of FIG. 48 reflectsthe power of the signal of the 37^(th) segment. Similarly, the signalpower of the 10^(th) segment should be in a constant relation with thepower of the CIR of the 10^(th) segment (i.e., CIR(10)), which isgenerated by using CIR(37) and CIR(53) in the extrapolation process.Therefore, the ratio between the power of a receive signal on the10^(th) segment and the power of the CIR(10) of the 10^(th) segment insection [f], which is generated by extrapolation, and the ratio betweenthe power of a receive signal of the 37^(th) segment and the power ofCIR(37) including the field synchronization data, which is generated byusing the field synchronization data, should be maintained identically(or equally). This is shown in Equation 20 below.CIR PWR(10)/signal PWR(10)=CIR PWR(37)/signal PWR(37)  Equation 20

Herein, CIR PWR(10) corresponds to the power of the CIR generated in the10^(th) segment within the extrapolation section, section [f], throughextrapolation, and the signal PWR(10) corresponds to the power of thereceive signal of the 10^(th) segment within the extrapolation section,section [f]. Also, CIR PWR(37) corresponds to the power of the CIRestimated in the training section (e.g., field synchronization section)using the field synchronization data, and signal PWR(37) corresponds tothe power of the receive signal of the 37^(th) segment including thefield synchronization data. However, as described above, the power ofCIR(10), which is generated by extrapolation using CIR(37) and CIR(53),may not satisfy the relation shown in Equation 20, due to unintendeddistortion. Therefore, the present invention calculates an α value thatcan satisfy Equation 21 shown below, thereby compensating the CIR powerof a specific segment within the extrapolation section (e.g., the10^(th) segment).α*CIR PWR(10)/signal PWR(10)=CIR PWR(37)/signal PWR(37)  Equation 21

More specifically, by obtaining the a value, and by multiplying thepower of the CIR generated in the specific segment within theextrapolation section through extrapolation by the obtained α value, theproportional relation between the power of the signal measured in thespecific segment and the power of the CIR estimated throughextrapolation in the specific segment within the extrapolation sectionand the proportional relation between the power of the signal measuredin the training section and the power of the CIR also measured in thetraining section become identical. As described above, by adjusting thepower of the CIR corresponding to the extrapolation section, problems ofunintended increase or decrease in signal power may be reduced.

For example, as shown in FIG. 48, if the power of CIR(10) generated inthe 10^(th) segment within the extrapolation section throughextrapolation is multiplied by an a value that can satisfy Equation 21,the proportional relation between the power of the signal measured inthe 10^(th) segment and the power of the CIR generated in the 10^(th)segment through extrapolation and the proportional relation between thepower of the signal and the power of the CIR both measured in the fieldsynchronization section become equal to one another.

FIG. 49 illustrates a channel equalizer according to an embodiment ofthe present invention.

FIG. 49 illustrates a block diagram of a channel equalizer according toan embodiment of the present invention. Referring to FIG. 49, thechannel equalizer includes a first frequency domain converter 4100, achannel estimator 4110, a second frequency domain converter 4121, acoefficient calculator 4122, a distortion compensator 4130, and a timedomain converter 4140. Herein, the channel equalizer may further includea remaining carrier phase error remover, a noise canceller (NC), and adecision unit.

The first frequency domain converter 4100 includes an overlap unit 4101overlapping inputted data, and a fast fourier transform (FFT) unit 4102converting the data outputted from the overlap unit 4101 to frequencydomain data.

The channel estimator 4110 includes a CIR estimator 4111, a firstcleaner 4113, a CIR calculator 4114, a second cleaner, and azero-padding unit. Herein, the channel estimator 4110 may furtherinclude a phase compensator compensating a phase of the CIR whichestimated in the CIR estimator 4111.

The second frequency domain converter 4121 includes a fast fouriertransform (FFT) unit converting the CIR being outputted from the channelestimator 4110 to frequency domain CIR.

The time domain converter 4140 includes an IFFT unit 4141 converting thedata having the distortion compensated by the distortion compensator4130 to time domain data, and a save unit 4142 extracting only validdata from the data outputted from the IFFT unit 4141. The output datafrom the save unit 4142 corresponds to the channel-equalized data.

If the remaining carrier phase error remover is connected to an outputterminal of the time domain converter 4140, the remaining carrier phaseerror remover estimates the remaining carrier phase error included inthe channel-equalized data, thereby removing the estimated error. If thenoise remover is connected to an output terminal of the time domainconverter 4140, the noise remover estimates noise included in thechannel-equalized data, thereby removing the estimated noise.

More specifically, the receiving data demodulated in FIG. 49 areoverlapped by the overlap unit 4101 of the first frequency domainconverter 4100 at a pre-determined overlapping ratio, which are thenoutputted to the FFT unit 4102. The FFT unit 4102 converts theoverlapped time domain data to overlapped frequency domain data throughby processing the data with FFT. Then, the converted data are outputtedto the distortion compensator 4130.

The distortion compensator 4130 performs a complex number multiplicationon the overlapped frequency domain data outputted from the FFT unit 4102included in the first frequency domain converter 4100 and theequalization coefficient calculated from the coefficient calculator4122, thereby compensating the channel distortion of the overlapped dataoutputted from the FFT unit 4102. Thereafter, the compensated data areoutputted to the IFFT unit 4141 of the time domain converter 4140. TheIFFT unit 4141 performs IFFT on the overlapped data having the channeldistortion compensated, thereby converting the overlapped data to timedomain data, which are then outputted to the save unit 4142. The saveunit 4142 extracts valid data from the data of the channel-equalized andoverlapped in the time domain, and outputs the extracted valid data.

Meanwhile, the received data are inputted to the overlap unit 4101 ofthe first frequency domain converter 4100 included in the channelequalizer and, at the same time, inputted to the CIR estimator 4111 ofthe channel estimator 4110.

The CIR estimator 4111 uses a training sequence, for example, data beinginputted during the known data section and the known data in order toestimate the CIR. If the data to be channel-equalizing is the datawithin the data group including field synchronization data, the trainingsequence using in the CIR estimator 4111 may become the fieldsynchronization data and known data. Meanwhile, if the data to bechannel-equalizing is the data within the data group not including fieldsynchronization data, the training sequence using in the CIR estimator4111 may become only the known data.

For example, the CIR estimator 4111 estimates CIR using the known datacorrespond to reference known data generated during the known datasection by the receiving system in accordance with an agreement betweenthe receiving system and the transmitting system. For this, the CIRestimator 4111 is provided known data position information from theknown sequence detector 2004. Also the CIR estimator 4111 may beprovided field synchronization position information from the knownsequence detector 2004.

The estimated CIR passes through the first cleaner (or pre-CIR cleaner)4113 or bypasses the first cleaner 4113, thereby being inputted to theCIR calculator (or CIR interpolator-extrapolator) 4114. The CIRcalculator 4114 either interpolates or extrapolates an estimated CIR,which is then outputted to the second cleaner (or post-CIR cleaner)4115.

The first cleaner 4113 may or may not operate depending upon whether theCIR calculator 4114 interpolates or extrapolates the estimated CIR. Forexample, if the CIR calculator 4114 interpolates the estimated CIR, thefirst cleaner 4113 does not operate. Conversely, if the CIR calculator4114 extrapolates the estimated CIR, the first cleaner 4113 operates.

More specifically, the CIR estimated from the known data includes achannel element that is to be obtained as well as a jitter elementcaused by noise. Since such jitter element deteriorates the performanceof the equalizer, it preferable that a coefficient calculator 4122removes the jitter element before using the estimated CIR. Therefore,according to the embodiment of the present invention, each of the firstand second cleaners 4113 and 4115 removes a portion of the estimated CIRhaving a power level lower than the predetermined threshold value (i.e.,so that the estimated CIR becomes equal to ‘0’). Herein, this removalprocess will be referred to as a “CIR cleaning” process.

The CIR calculator 4114 performs CIR interpolation by multiplying a1least two or more CIRs estimated from the CIR estimator 4111 by each ofcoefficients, thereby adding the multiplied values. According to anembodiment of the present invention, by using two CIRs estimated in thetraining section, the CIR of the general data section located betweentraining sections may be generated through linear interpolation.According to another embodiment of the present invention, by applying 5CIRs estimated in the training section to Equation 15 and Equation 18,the CIR of the general data section located between training sectionsmay be generated through cubic spline interpolation. At this point, someof the noise elements of the CIR may be added to one another, therebybeing cancelled. Therefore, when the CIR calculator 4114 performs CIRinterpolation, the original (or initial) CIR having noise elementsremaining therein. In other words, when the CIR calculator 4114 performsCIR interpolation, the estimated CIR bypasses the first cleaner 4113 andis inputted to the CIR calculator 4114. Subsequently, the second cleaner4115 cleans the CIR interpolated by the CIR interpolator-extrapolator4114.

Conversely, in the CIR Interpolator/Extrapolator 4114, CIR extrapolationis performed by using the difference between two CIRs estimated by theCIR estimator 4112, so as to estimate the CIR located outside of the twoCIRs (i.e., the CIR of the extrapolation section). At this point,according to an embodiment of the present invention, the power of theCIR generated in the specific segment through extrapolation iscompensated so that the proportional relation between the power of thesignal measured in the specific segment within the extrapolation sectionand the power of the CIR estimated through extrapolation in the specificsegment within the extrapolation section can become identical to theproportional relation between the power of the signal and the power ofthe CIR both measured in the training section. However, when performingextrapolation as described above, the noise element of the CIR mayrather be amplified. Accordingly, when the CIR calculator 4114 performsCIR extrapolation, the CIR cleaned by the first cleaner 4113 is used.More specifically, when the CIR calculator 4114 performs CIRextrapolation, the extrapolated CIR passes through the second cleaner4115, thereby being inputted to the zero-padding unit 4116.

Meanwhile, when a second frequency domain converter (or fast fouriertransform (FFT2)) 4121 converts the CIR, which has been cleaned andoutputted from the second cleaner 4115, to a frequency domain, thelength and of the inputted CIR and the FFT size may not match (or beidentical to one another). In other words, the CIR length may be smallerthan the FFT size. In this case, the zero-padding unit 4116 adds anumber of zeros ‘0’s corresponding to the difference between the FFTsize and the CIR length to the inputted CIR, thereby outputting theprocessed CIR to the second frequency domain converter (FFT2) 4121.Herein, the zero-padded CIR may correspond to one of the interpolatedCIR, extrapolated CIR, and the CIR estimated in the known data section.

The second frequency domain converter 4121 performs FFT on the CIR beingoutputted from the zero padding unit 4116, thereby converting the CIR toa frequency domain CIR. Then, the second frequency domain converter 4121outputs the converted CIR to the coefficient calculator 4122.

The coefficient calculator 4122 uses the frequency domain CIR beingoutputted from the second frequency domain converter 4121 to calculatethe equalization coefficient. Then, the coefficient calculator 4122outputs the calculated coefficient to the distortion compensator 4130.Herein, for example, the coefficient calculator 4122 calculates achannel equalization coefficient of the frequency domain that canprovide minimum mean square error (MMSE) from the CIR of the frequencydomain, which is outputted to the distortion compensator 4130.

The distortion compensator 4130 performs a complex number multiplicationon the overlapped data of the frequency domain being outputted from theFFT unit 4102 of the first frequency domain converter 4100 and theequalization coefficient calculated by the coefficient calculator 4122,thereby compensating the channel distortion of the overlapped data beingoutputted from the FFT unit 4102.

Block Decoder

Meanwhile, if the data being inputted to the block decoder 2005, afterbeing channel-equalized by the equalizer 2003, correspond to the datahaving both block encoding and trellis encoding performed thereon (i.e.,the data within the RS frame, the signaling information data, etc.) bythe transmitting system, trellis decoding and block decoding processesare performed on the inputted data as inverse processes of thetransmitting system. Alternatively, if the data being inputted to theblock decoder 2005 correspond to the data having only trellis encodingperformed thereon (i.e., the main service data), and not the blockencoding, only the trellis decoding process is performed on the inputteddata as the inverse process of the transmitting system.

The trellis decoded and block decoded data by the block decoder 2005 arethen outputted to the RS frame decoder 2006. More specifically, theblock decoder 2005 removes the known data, data used for trellisinitialization, and signaling information data, MPEG header, which havebeen inserted in the data group, and the RS parity data, which have beenadded by the RS encoder/non-systematic RS encoder or non-systematic RSencoder of the transmitting system. Then, the block decoder 2005 outputsthe processed data to the RS frame decoder 2006. Herein, the removal ofthe data may be performed before the block decoding process, or may beperformed during or after the block decoding process.

Meanwhile, the data trellis-decoded by the block decoder 2005 areoutputted to the data deinterleaver of the main service data processor2008. At this point, the data being trellis-decoded by the block decoder2005 and outputted to the data deinterleaver may not only include themain service data but may also include the data within the RS frame andthe signaling information. Furthermore, the RS parity data that areadded by the transmitting system after the pre-processor 230 may also beincluded in the data being outputted to the data deinterleaver.

According to another embodiment of the present invention, data that arenot processed with block decoding and only processed with trellisencoding by the transmitting system may directly bypass the blockdecoder 2005 so as to be outputted to the data deinterleaver. In thiscase, a trellis decoder should be provided before the datadeinterleaver. More specifically, if the inputted data correspond to thedata having only trellis encoding performed thereon and not blockencoding, the block decoder 2005 performs Viterbi (or trellis) decodingon the inputted data so as to output a hard decision value or to performa hard-decision on a soft decision value, thereby outputting the result.

Meanwhile, if the inputted data correspond to the data having both blockencoding process and trellis encoding process performed thereon, theblock decoder 2005 outputs a soft decision value with respect to theinputted data.

In other words, if the inputted data correspond to data being processedwith block encoding by the block processor 302 and being processed withtrellis encoding by the trellis encoding module 256, in the transmittingsystem, the block decoder 2005 performs a decoding process and a trellisdecoding process on the inputted data as inverse processes of thetransmitting system. At this point, the RS frame encoder of thepre-processor included in the transmitting system may be viewed as anouter (or external) encoder. And, the trellis encoder may be viewed asan inner (or internal) encoder. When decoding such concatenated codes,in order to allow the block decoder 2005 to maximize its performance ofdecoding externally encoded data, the decoder of the internal codeshould output a soft decision value.

FIG. 50 illustrates a detailed block diagram of the block decoder 2005according to an embodiment of the present invention. Referring to FIG.50, the block decoder 2005 includes a feedback controller 4010, an inputbuffer 4011, a trellis decoding unit (or 12-way trellis coded modulation(TCM) decoder or inner decoder) 4012, a symbol-byte converter 4013, anouter block extractor 4014, a feedback deformatter 4015, a symboldeinterleaver 4016, an outer symbol mapper 4017, a symbol decoder 4018,an inner symbol mapper 4019, a symbol interleaver 4020, a feedbackformatter 4021, and an output buffer 4022. Herein, just as in thetransmitting system, the trellis decoding unit 4012 may be viewed as aninner (or internal) decoder. And, the symbol decoder 4018 may be viewedas an outer (or external) decoder.

The input buffer 4011 temporarily stores the mobile service data symbolsbeing channel-equalized and outputted from the equalizer 2003. (Herein,the mobile service data symbols may include symbols corresponding to thesignaling information, RS parity data symbols and CRC data symbols addedduring the encoding process of the RS frame.) Thereafter, the inputbuffer 4011 repeatedly outputs the stored symbols for M number of timesto the trellis decoding unit 4012 in a turbo block (TDL) size requiredfor the turbo decoding process.

The turbo decoding length (TDL) may also be referred to as a turboblock. Herein, a TDL should include at least one SCCC block size.Therefore, as defined in FIG. 5, when it is assumed that one M/H blockis a 16-segment unit, and that a combination of 10 M/H blocks form oneSCCC block, a TDL should be equal to or larger than the maximum possiblecombination size. For example, when it is assumed that 2 M/H blocks formone SCCC block, the TDL may be equal to or larger than 32 segments(i.e., 828×32=26496 symbols). Herein, M indicates a number ofrepetitions for turbo-decoding pre-decided by the feed-back controller4010.

Also, M represents a number of repetitions of the turbo decodingprocess, the number being predetermined by the feedback controller 4010.

Additionally, among the values of symbols being channel-equalized andoutputted from the equalizer 2003, the input symbol values correspondingto a section having no mobile service data symbols (including RS paritydata symbols during RS frame encoding and CRC data symbols) includedtherein, bypass the input buffer 4011 without being stored. Morespecifically, since trellis-encoding is performed on input symbol valuesof a section wherein SCCC block-encoding has not been performed, theinput buffer 4011 inputs the inputted symbol values of the correspondingsection directly to the trellis encoding module 4012 without performingany storage, repetition, and output processes. The storage, repetition,and output processes of the input buffer 4011 are controlled by thefeedback controller 4010. Herein, the feedback controller 4010 refers toSCCC-associated information (e.g., SCCC block mode and SCCC outer codemode), which are outputted from the signaling decoder 2013 or theoperation controller 2000, in order to control the storage and outputprocesses of the input buffer 4011.

The trellis decoding unit 4012 includes a 12-way TCM decoder. Herein,the trellis decoding unit 4012 performs 12-way trellis decoding asinverse processes of the 12-way trellis encoder.

More specifically, the trellis decoding unit 4012 receives a number ofoutput symbols of the input buffer 4011 and soft-decision values of thefeedback formatter 4021 equivalent to each TDL, so as to perform the TCMdecoding process.

At this point, based upon the control of the feedback controller 4010,the soft-decision values outputted from the feedback formatter 4021 arematched with a number of mobile service data symbol places so as to bein a one-to-one (1:1) correspondence. Herein, the number of mobileservice data symbol places is equivalent to the TDL being outputted fromthe input buffer 4011.

More specifically, the mobile service data being outputted from theinput buffer 4011 are matched with the turbo decoded data beinginputted, so that each respective data place can correspond with oneanother. Thereafter, the matched data are outputted to the trellisdecoding unit 4012. For example, if the turbo decoded data correspond tothe third symbol within the turbo block, the corresponding symbol (ordata) is matched with the third symbol included in the turbo block,which is outputted from the input buffer 4011. Subsequently, the matchedsymbol (or data) is outputted to the trellis decoding unit 4012.

In order to do so, while the regressive turbo decoding is in process,the feedback controller 4010 controls the input buffer 4011 so that theinput buffer 4011 stores the corresponding turbo block data. Also, bydelaying data (or symbols), the soft decision value (e.g., LLR) of thesymbol outputted from the symbol interleaver 4020 and the symbol of theinput buffer 4011 corresponding to the same place (or position) withinthe block of the output symbol are matched with one another to be in aone-to-one correspondence. Thereafter, the matched symbols arecontrolled so that they can be inputted to the TCM decoder through therespective path. This process is repeated for a predetermined number ofturbo decoding cycle periods. Then, the data of the next turbo block areoutputted from the input buffer 4011, thereby repeating the turbodecoding process.

The output of the trellis decoding unit 4012 signifies a degree ofreliability of the transmission bits configuring each symbol. Forexample, in the transmitting system, since the input data of the trellisencoding module correspond to two bits as one symbol, a log likelihoodratio (LLR) between the likelihood of a bit having the value of ‘1’ andthe likelihood of the bit having the value of ‘0’ may be respectivelyoutputted (in bit units) to the upper bit and the lower bit. Herein, thelog likelihood ratio corresponds to a log value for the ratio betweenthe likelihood of a bit having the value of ‘1’ and the likelihood ofthe bit having the value of ‘0’. Alternatively, a LLR for the likelihoodof 2 bits (i.e., one symbol) being equal to “00”, “01”, “10”, and “11”may be respectively outputted (in symbol units) to all 4 combinations ofbits (i.e., 00, 01, 10, 11). Consequently, this becomes the softdecision value that indicates the degree of reliability of thetransmission bits configuring each symbol. A maximum a posterioriprobability (MAP) or a soft-out Viterbi algorithm (SOYA) may be used asa decoding algorithm of each TCM decoder within the trellis decodingunit 4012.

The output of the trellis decoding unit 4012 is inputted to thesymbol-byte converter 4013 and the outer block extractor 4014.

The symbol-byte converter 4013 performs a hard-decision process of thesoft decision value that is trellis decoded and outputted from thetrellis decoding unit 4012. Thereafter, the symbol-byte converter 4013groups 4 symbols into byte units, which are then outputted to the datadeinterleaver of the main service data processor 2008 of FIG. 41. Morespecifically, the symbol-byte converter 4013 performs hard-decision inbit units on the soft decision value of the symbol outputted from thetrellis decoding unit 4012. Therefore, the data processed withhard-decision and outputted in bit units from the symbol-byte converter4013 not only include main service data, but may also include mobileservice data, known data, RS parity data, and MPEG headers.

Among the soft decision values of TDL size of the trellis decoding unit4012, the outer block extractor 4014 identifies the soft decision valuesof B size of corresponding to the mobile service data symbols (whereinsymbols corresponding to signaling information, RS parity data symbolsthat are added during the encoding of the RS frame, and CRC data symbolsare included) and outputs the identified soft decision values to thefeedback deformatter 4015.

The feedback deformatter 4015 changes the processing order of the softdecision values corresponding to the mobile service data symbols. Thisis an inverse process of an initial change in the processing order ofthe mobile service data symbols, which are generated during anintermediate step, wherein the output symbols outputted from the blockprocessor 302 of the transmitting system are being inputted to thetrellis encoding module 256 (e.g., when the symbols pass through thegroup formatter, the data deinterleaver, the packet formatter, and thedata interleaver). Thereafter, the feedback deformatter 2015 performsreordering of the process order of soft decision values corresponding tothe mobile service data symbols and, then, outputs the processed mobileservice data symbols to the symbol deinterleaver 4016.

This is because a plurality of blocks exist between the block processor302 and the trellis encoding module 256, and because, due to theseblocks, the order of the mobile service data symbols being outputtedfrom the block processor 302 and the order of the mobile service datasymbols being inputted to the trellis encoding module 256 are notidentical to one another. Therefore, the feedback deformatter 4015reorders (or rearranges) the order of the mobile service data symbolsbeing outputted from the outer block extractor 4014, so that the orderof the mobile service data symbols being inputted to the symboldeinterleaver 4016 matches the order of the mobile service data symbolsoutputted from the block processor 302 of the transmitting system. Thereordering process may be embodied as one of software, middleware, andhardware.

The symbol deinterleaver 4016 performs deinterleaving on the mobileservice data symbols having their processing orders changed andoutputted from the feedback deformatter 4015, as an inverse process ofthe symbol interleaving process of the symbol interleaver 514 includedin the transmitting system. The size of the block used by the symboldeinterleaver 4016 during the deinterleaving process is identical tointerleaving size of an actual symbol (i.e., B) of the symbolinterleaver 514, which is included in the transmitting system. This isbecause the turbo decoding process is performed between the trellisdecoding unit 4012 and the symbol decoder 4018. Both the input andoutput of the symbol deinterleaver 4016 correspond to soft decisionvalues, and the deinterleaved soft decision values are outputted to theouter symbol mapper 4017.

The operations of the outer symbol mapper 4017 may vary depending uponthe structure and coding rate of the convolution encoder 513 included inthe transmitting system. For example, when data are 1/2-rate encoded bythe convolution encoder 513 and then transmitted, the outer symbolmapper 4017 directly outputs the input data without modification. Inanother example, when data are 1/4-rate encoded by the convolutionencoder 513 and then transmitted, the outer symbol mapper 4017 convertsthe input data so that it can match the input data format of the symboldecoder 4018. For this, the outer symbol mapper 4017 may be inputtedSCCC-associated information (i.e., SCCC block mode and SCCC outer codemode) from the signaling decoder 2013. Then, the outer symbol mapper4017 outputs the converted data to the symbol decoder 4018.

The symbol decoder 4018 (i.e., the outer decoder) receives the dataoutputted from the outer symbol mapper 4017 and performs symbol decodingas an inverse process of the convolution encoder 513 included in thetransmitting system. At this point, two different soft decision valuesare outputted from the symbol decoder 4018. One of the outputted softdecision values corresponds to a soft decision value matching the outputsymbol of the convolution encoder 513 (hereinafter referred to as a“first decision value”). The other one of the outputted soft decisionvalues corresponds to a soft decision value matching the input bit ofthe convolution encoder 513 (hereinafter referred to as a “seconddecision value”).

More specifically, the first decision value represents a degree ofreliability the output symbol (i.e., 2 bits) of the convolution encoder513. Herein, the first soft decision value may output (in bit units) aLLR between the likelihood of 1 bit being equal to ‘1’ and thelikelihood of 1 bit being equal to ‘0’ with respect to each of the upperbit and lower bit, which configures a symbol. Alternatively, the firstsoft decision value may also output (in symbol units) a LLR for thelikelihood of 2 bits being equal to “00”, “01”, “10”, and “11” withrespect to all possible combinations. The first soft decision value isfed-back to the trellis decoding unit 4012 through the inner symbolmapper 4019, the symbol interleaver 4020, and the feedback formatter4021. On the other hand, the second soft decision value indicates adegree of reliability the input bit of the convolution encoder 513included in the transmitting system. Herein, the second soft decisionvalue is represented as the LLR between the likelihood of 1 bit beingequal to ‘1’ and the likelihood of bit being equal to ‘0’. Thereafter,the second soft decision value is outputted to the outer buffer 4022. Inthis case, a maximum a posteriori probability (MAP) or a soft-outViterbi algorithm (SOYA) may be used as the decoding algorithm of thesymbol decoder 4018.

The first soft decision value that is outputted from the symbol decoder4018 is inputted to the inner symbol mapper 4019. The inner symbolmapper 4019 converts the first soft decision value to a data formatcorresponding the input data of the trellis decoding unit 4012.Thereafter, the inner symbol mapper 4019 outputs the converted softdecision value to the symbol interleaver 4020. The operations of theinner symbol mapper 4019 may also vary depending upon the structure andcoding rate of the convolution encoder 513 included in the transmittingsystem.

The symbol interleaver 4020 performs symbol interleaving, as shown inFIG. 30, on the first soft decision value that is outputted from theinner symbol mapper 4019. Then, the symbol interleaver 4020 outputs thesymbol-interleaved first soft decision value to the feedback formatter4021. Herein, the output of the symbol interleaver 4020 also correspondsto a soft decision value.

With respect to the changed processing order of the soft decision valuescorresponding to the symbols that are generated during an intermediatestep, wherein the output symbols outputted from the block processor 302of the transmitting system are being inputted to the trellis encodingmodule (e.g., when the symbols pass through the group formatter, thedata deinterleaver, the packet formatter, the RS encoder, and the datainterleaver), the feedback formatter 4021 alters (or changes) the orderof the output values outputted from the symbol interleaver 4020.Subsequently, the feedback formatter 4020 outputs values to the trellisdecoding unit 4012 in the changed order. The reordering process of thefeedback formatter 4021 may configure at least one of software,hardware, and middleware.

The soft decision values outputted from the symbol interleaver 4020 arematched with the positions of mobile service data symbols each havingthe size of TDL, which are outputted from the input buffer 4011, so asto be in a one-to-one correspondence. Thereafter, the soft decisionvalues matched with the respective symbol position are inputted to thetrellis decoding unit 4012. At this point, since the main service datasymbols or the RS parity data symbols and known data symbols of the mainservice data do not correspond to the mobile service data symbols, thefeedback formatter 4021 inserts null data in the correspondingpositions, thereby outputting the processed data to the trellis decodingunit 4012. Additionally, each time the symbols having the size of TDLare turbo decoded, no value is fed-back by the symbol interleaver 4020starting from the beginning of the first decoding process. Therefore,the feedback formatter 4021 is controlled by the feedback controller4010, thereby inserting null data into all symbol positions including amobile service data symbol. Then, the processed data are outputted tothe trellis decoding unit 4012.

The output buffer 4022 receives the second soft decision value from thesymbol decoder 4018 based upon the control of the feedback controller4010. Then, the output buffer 4022 temporarily stores the receivedsecond soft decision value. Thereafter, the output buffer 4022 outputsthe second soft decision value to the RS frame decoder 2006. Forexample, the output buffer 4022 overwrites the second soft decisionvalue of the symbol decoder 4018 until the turbo decoding process isperformed for M number of times. Then, once all M number of turbodecoding processes is performed for a single TDL, the correspondingsecond soft decision value is outputted to the RS frame decoder 2006.

The feedback controller 4010 controls the number of turbo decoding andturbo decoding repetition processes of the overall block decoder, shownin FIG. 50. More specifically, once the turbo decoding process has beenrepeated for a predetermined number of times, the second soft decisionvalue of the symbol decoder 4018 is outputted to the RS frame decoder2006 through the output buffer 4022. Thus, the block decoding process ofa turbo block is completed. In the description of the present invention,this process is referred to as a regressive turbo decoding process forsimplicity.

At this point, the number of regressive turbo decoding rounds betweenthe trellis decoding unit 4012 and the symbol decoder 4018 may bedefined while taking into account hardware complexity and errorcorrection performance. Accordingly, if the number of rounds increases,the error correction performance may be enhanced. However, this may leadto a disadvantageous of the hardware becoming more complicated (orcomplex).

Meanwhile, the main service data processor 2008 corresponds to blockrequired for receiving the main service data. Therefore, theabove-mentioned blocks may not be necessary (or required) in thestructure of a digital broadcast receiving system for receiving mobileservice data only.

The data deinterleaver of the main service data processor 2008 performsan inverse process of the data interleaver included in the transmittingsystem. In other words, the data deinterleaver deinterleaves the mainservice data outputted from the block decoder 2005 and outputs thedeinterleaved main service data to the RS decoder. The data beinginputted to the data deinterleaver include main service data, as well asmobile service data, known data, RS parity data, and an MPEG header. Atthis point, among the inputted data, only the main service data and theRS parity data added to the main service data packet may be outputted tothe RS decoder. Also, all data outputted after the data derandomizer mayall be removed with the exception for the main service data. In theembodiment of the present invention, only the main service data and theRS parity data added to the main service data packet are inputted to theRS decoder.

The RS decoder performs a systematic RS decoding process on thedeinterleaved data and outputs the processed data to the dataderandomizer.

The data derandomizer receives the output of the RS decoder andgenerates a pseudo random data byte identical to that of the randomizerincluded in the digital broadcast transmitting system. Thereafter, thedata derandomizer performs a bitwise exclusive OR (XOR) operation on thegenerated pseudo random data byte, thereby inserting the MPEGsynchronization bytes to the beginning of each packet so as to outputthe data in 188-byte main service data packet units.

RS Frame Decoder

The data outputted from the block decoder 2005 are in portion units.More specifically, in the transmitting system, the RS frame is dividedinto several portions, and the mobile service data of each portion areassigned either to regions A/B/C/D within the data group or to any oneof regions A/B and regions C/D, thereby being transmitted to thereceiving system. Therefore, the RS frame decoder 2006 groups severalportions included in a parade so as to form an RS frame. Alternatively,the RS frame decoder 2006 may also group several portions included in aparade so as to form two RS frames. Thereafter, error correctiondecoding is performed in RS frame units.

For example, when the RS frame mode value is equal to ‘00’, then oneparade transmits one RS frame. At this point, one RS frame is dividedinto several portions, and the mobile service data of each portion areassigned to regions A/B/C/D of the corresponding data group, therebybeing transmitted. In this case, the RS frame decoder 2006 extractsmobile service data from regions A/B/C/D of the corresponding datagroup, as shown in FIG. 51( a). Subsequently, the RS frame decoder 2006may perform the process of forming (or creating) a portion on aplurality of data group within a parade, thereby forming severalportions. Then, the several portions of mobile service data may begrouped to form an RS frame. Herein, if stuffing bytes are added to thelast portion, the RS frame may be formed after removing the stuffingbyte.

In another example, when the RS frame mode value is equal to ‘01’, thenone parade transmits two RS frames (i.e., a primary RS frame and asecondary RS frame). At this point, a primary RS frame is divided intoseveral primary portions, and the mobile service data of each primaryportion are assigned to regions A/B of the corresponding data group,thereby being transmitted. Also, a secondary RS frame is divided intoseveral secondary portions, and the mobile service data of eachsecondary portion are assigned to regions C/D of the corresponding datagroup, thereby being transmitted.

In this case, the RS frame decoder 2006 extracts mobile service datafrom regions A/B of the corresponding data group, as shown in FIG. 51(b). Subsequently, the RS frame decoder 2006 may perform the process offorming (or creating) a primary portion on a plurality of data groupwithin a parade, thereby forming several primary portions. Then, theseveral primary portions of mobile service data may be grouped to form aprimary RS frame. Herein, if stuffing bytes are added to the lastprimary portion, the primary RS frame may be formed after removing thestuffing byte. Also, the RS frame decoder 2006 extracts mobile servicedata from regions C/D of the corresponding data group. Subsequently, theRS frame decoder 2006 may perform the process of forming (or creating) asecondary portion on a plurality of data group within a parade, therebyforming several secondary portions. Then, the several secondary portionsof mobile service data may be grouped to form a secondary RS frame.Herein, if stuffing bytes are added to the last secondary portion, thesecondary RS frame may be formed after removing the stuffing byte.

More specifically, the RS frame decoder 2006 receives the RS-encodedand/or CRC-encoded mobile service data of each portion from the blockdecoder 2005. Then, the RS frame decoder 2006 groups several portions,which are inputted based upon RS frame-associated information outputtedfrom the signaling decoder 2013 or the operation controller 2000,thereby performing error correction. By referring to the RS frame modevalue included in the RS frame-associated information, the RS framedecoder 2006 may form an RS frame and may also be informed of the numberof RS code parity data bytes and the code size. Herein, the RS code isused to configure (or form) the RS frame. The RS frame decoder 2006 alsorefers to the RS frame-associated information in order to perform aninverse process of the RS frame encoder, which is included in thetransmitting system, thereby correcting the errors within the RS frame.Thereafter, the RS frame decoder 2006 adds 1 MPEG synchronization databyte to the error-correction mobile service data packet. In an earlierprocess, the 1 MPEG synchronization data byte was removed from themobile service data packet during the RS frame encoding process.Finally, the RS frame decoder 2006 performs a derandomizing process onthe processed mobile service data packet.

FIG. 52 illustrates, when the RS frame mode value is equal to ‘00’, anexemplary process of grouping several portion being transmitted to aparade, thereby forming an RS frame and an RS frame reliability map.

More specifically, the RS frame decoder 2006 receives and groups aplurality of mobile service data bytes, so as to form an RS frame.According to the present invention, in transmitting system, the mobileservice data correspond to data RS-encoded in RS frame units. At thispoint, the mobile service data may already be error correction encoded(e.g., CRC-encoded). Alternatively, the error correction encodingprocess may be omitted.

It is assumed that, in the transmitting system, an RS frame having thesize of (N+2)×(187+P) bytes is divided into M number of portions, andthat the M number of mobile service data portions are assigned andtransmitted to regions A/B/C/D in M number of data groups, respectively.In this case, in the receiving system, each mobile service data portionis grouped, as shown in FIG. 52( a), thereby forming an RS frame havingthe size of (N+2)×(187+P) bytes. At this point, when stuffing bytes (S)are added to at least one portion included in the corresponding RS frameand then transmitted, the stuffing bytes are removed, therebyconfiguring an RS frame and an RS frame reliability map. For example, asshown in FIG. 27, when S number of stuffing bytes are added to thecorresponding portion, the S number of stuffing bytes are removed,thereby configuring the RS frame and the RS frame reliability map.

Herein, when it is assumed that the block decoder 2005 outputs a softdecision value for the decoding result, the RS frame decoder 2006 maydecide the ‘0’ and ‘1’ of the corresponding bit by using the codes ofthe soft decision value. 8 bits that are each decided as described aboveare grouped to generate 1 data byte. If the above-described process isperformed on all soft decision values of several portions (or datagroups) included in a parade, the RS frame having the size of(N+2)×(187+P) bytes may be configured.

Additionally, the present invention uses the soft decision value notonly to configure the RS frame but also to configure a reliability map.

Herein, the reliability map indicates the reliability of thecorresponding data byte, which is configured by grouping 8 bits, the 8bits being decided by the codes of the soft decision value.

For example, when the absolute value of the soft decision value exceedsa pre-determined threshold value, the value of the corresponding bit,which is decided by the code of the corresponding soft decision value,is determined to be reliable. Conversely, when the absolute value of thesoft decision value does not exceed the pre-determined threshold value,the value of the corresponding bit is determined to be unreliable.Thereafter, if even a single bit among the 8 bits, which are decided bythe codes of the soft decision value and group to configure one databyte, is determined to be unreliable, the corresponding data byte ismarked on the reliability map as an unreliable data byte.

Herein, determining the reliability of one data byte is only exemplary.More specifically, when a plurality of data bytes (e.g., at least 4 databytes) are determined to be unreliable, the corresponding data bytes mayalso be marked as unreliable data bytes within the reliability map.Conversely, when all of the data bits within the one data byte aredetermined to be reliable (i.e., when the absolute value of the softdecision values of all 8 bits included in the one data byte exceed thepredetermined threshold value), the corresponding data byte is marked tobe a reliable data byte on the reliability map. Similarly, when aplurality of data bytes (e.g., at least 4 data bytes) are determined tobe reliable, the corresponding data bytes may also be marked as reliabledata bytes within the reliability map. The numbers proposed in theabove-described example are merely exemplary and, therefore, do notlimit the scope or spirit of the present invention.

The process of configuring the RS frame and the process of configuringthe reliability map both using the soft decision value may be performedat the same time. Herein, the reliability information within thereliability map is in a one-to-one correspondence with each byte withinthe RS frame. For example, if a RS frame has the size of (N+2)×(187+P)bytes, the reliability map is also configured to have the size of(N+2)×(187+P) bytes. FIG. 52( a′) and FIG. 52( b′) respectivelyillustrate the process steps of configuring the reliability mapaccording to the present invention.

Subsequently, the RS frame reliability map is used on the RS frames soas to perform error correction.

FIG. 53 illustrates example of the error correction processed accordingto embodiments of the present invention. FIG. 53 illustrates an exampleof performing an error correction process when the transmitting systemhas performed both RS encoding and CRC encoding processes on the RSframe.

As shown in FIG. 53( a) and FIG. 53( a′), when the RS frame having thesize of (N+2)×(187+P) bytes and the RS frame reliability map having thesize of (N+2)×(187+P) bytes are generated, a CRC syndrome checkingprocess is performed on the generated RS frame, thereby verifyingwhether any error has occurred in each row. Subsequently, as shown inFIG. 53( b), a 2-byte checksum is removed to configure an RS framehaving the size of N×(187+P) bytes. Herein, the presence (or existence)of an error is indicated on an error flag corresponding to each row.Similarly, since the portion of the reliability map corresponding to theCRC checksum has hardly any applicability, this portion is removed sothat only N×(187+P) number of the reliability information bytes remain,as shown in FIG. 53( b′).

After performing the CRC syndrome checking process, as described above,a RS decoding process is performed in a column direction. Herein, a RSerasure correction process may be performed in accordance with thenumber of CRC error flags. More specifically, as shown in FIG. 53( c),the CRC error flag corresponding to each row within the RS frame isverified. Thereafter, the RS frame decoder 2006 determines whether thenumber of rows having a CRC error occurring therein is equal to orsmaller than the maximum number of errors on which the RS erasurecorrection may be performed, when performing the RS decoding process ina column direction. The maximum number of errors corresponds to P numberof parity bytes inserted when performing the RS encoding process. In theembodiment of the present invention, it is assumed that 48 parity byteshave been added to each column (i.e., P=48).

If the number of rows having the CRC errors occurring therein is smallerthan or equal to the maximum number of errors (i.e., 48 errors accordingto this embodiment) that can be corrected by the RS erasure decodingprocess, a (235,187)-RS erasure decoding process is performed in acolumn direction on the RS frame having (187+P) number of N-byte rows(i.e., 235 N-byte rows), as shown in FIG. 53( d). Thereafter, as shownin FIG. 53( e), the 48-byte parity data that have been added at the endof each column are removed. Conversely, however, if the number of rowshaving the CRC errors occurring therein is greater than the maximumnumber of errors (i.e., 48 errors) that can be corrected by the RSerasure decoding process, the RS erasure decoding process cannot beperformed. In this case, the error may be corrected by performing ageneral RS decoding process. In addition, the reliability map, which hasbeen generated based upon the soft decision value along with the RSframe, may be used to further enhance the error correction ability (orperformance) of the present invention.

More specifically, the RS frame decoder 2006 compares the absolute valueof the soft decision value of the block decoder 2005 with thepre-determined threshold value, so as to determine the reliability ofthe bit value decided by the code of the corresponding soft decisionvalue. Also, 8 bits, each being determined by the code of the softdecision value, are grouped to form one data byte. Accordingly, thereliability information on this one data byte is indicated on thereliability map. Therefore, as shown in FIG. 53( c), even though aparticular row is determined to have an error occurring therein basedupon a CRC syndrome checking process on the particular row, the presentinvention does not assume that all bytes included in the row have errorsoccurring therein. The present invention refers to the reliabilityinformation of the reliability map and sets only the bytes that havebeen determined to be unreliable as erroneous bytes. In other words,with disregard to whether or not a CRC error exists within thecorresponding row, only the bytes that are determined to be unreliablebased upon the reliability map are set as erasure points.

According to another method, when it is determined that CRC errors areincluded in the corresponding row, based upon the result of the CRCsyndrome checking result, only the bytes that are determined by thereliability map to be unreliable are set as errors. More specifically,only the bytes corresponding to the row that is determined to haveerrors included therein and being determined to be unreliable based uponthe reliability information, are set as the erasure points. Thereafter,if the number of error points for each column is smaller than or equalto the maximum number of errors (i.e., 48 errors) that can be correctedby the RS erasure decoding process, an RS erasure decoding process isperformed on the corresponding column. Conversely, if the number oferror points for each column is greater than the maximum number oferrors (i.e., 48 errors) that can be corrected by the RS erasuredecoding process, a general decoding process is performed on thecorresponding column.

More specifically, if the number of rows having CRC errors includedtherein is greater than the maximum number of errors (i.e., 48 errors)that can be corrected by the RS erasure decoding process, either an RSerasure decoding process or a general RS decoding process is performedon a column that is decided based upon the reliability information ofthe reliability map, in accordance with the number of erasure pointswithin the corresponding column. For example, it is assumed that thenumber of rows having CRC errors included therein within the RS frame isgreater than 48. And, it is also assumed that the number of erasurepoints decided based upon the reliability information of the reliabilitymap is indicated as 40 erasure points in the first column and as erasurepoints in the second column. In this case, a (235,187)-RS erasuredecoding process is performed on the first column. Alternatively, a(235,187)-RS decoding process is performed on the second column. Whenerror correction decoding is performed on all column directions withinthe RS frame by using the above-described process, the 48-byte paritydata which were added at the end of each column are removed, as shown inFIG. 53( e).

As described above, even though the total number of CRC errorscorresponding to each row within the RS frame is greater than themaximum number of errors that can be corrected by the RS erasuredecoding process, when the number of bytes determined to have a lowreliability level, based upon the reliability information on thereliability map within a particular column, while performing errorcorrection decoding on the particular column. Herein, the differencebetween the general RS decoding process and the RS erasure decodingprocess is the number of errors that can be corrected. Morespecifically, when performing the general RS decoding process, thenumber of errors corresponding to half of the number of parity bytes(i.e., (number of parity bytes)/2) that are inserted during the RSencoding process may be error corrected (e.g., 24 errors may becorrected). Alternatively, when performing the RS erasure decodingprocess, the number of errors corresponding to the number of paritybytes that are inserted during the RS encoding process may be errorcorrected (e.g., 48 errors may be corrected).

After performing the error correction decoding process, as describedabove, a RS frame configured of 187 N-byte rows (or packet) may beobtained as shown in FIG. 53( e). The RS frame having the size of N×187bytes is outputted by the order of N number of 187-byte units. At thispoint, 1 MPEG synchronization byte, which had been removed by thetransmitting system, is added to each 187-byte packet, as shown in FIG.53( f). Therefore, a 188-byte unit mobile service data packet isoutputted.

At this point, the RS frame decoded mobile service data is performed aderandomizing process, which corresponds to the inverse process of therandomizer included in the transmitting system and then the derandomizeddata are outputted, thereby obtaining the mobile service datatransmitted from the transmitting system. In the present invention, theRS frame decoder 2006 may perform the data derandomizing function.

An RS frame decoder may be configured of M number of RS frame decodersprovided in parallel, wherein the number of RS frame encoders is equalto the number of parades (=M) within an M/H frame, a multiplexer formultiplexing each portion and being provided to each input end of the Mnumber of RS frame decoders, and a demultiplexer for demultiplexing eachportion and being provided to each output end of the M number of RSframe decoders.

As described above, the present invention has the following advantages.Herein, the present invention is robust (or strong) against any errorthat may occur when transmitting mobile broadcast service data through achannel. And, the present invention is also highly compatible to theconventional system.

Additionally, the present invention may also receive the mobilebroadcast service data without any error occurring, even in channelshaving severe ghost effect and noise.

Furthermore, by inserting known data in a specific position within adata region and by transmitting the processed data, the receivingperformance of a receiving system may be enhanced even in channelenvironments (or conditions) undergoing frequent channel changes.

Additionally, by estimating the CIR of the general data section locatedbetween training sections through cubic spline interpolation, so as tochannel-equalize the data of the corresponding section, thechannel-equalizing performance of the present invention may be enhancedeven in an environment undergoing frequent channel changes. Furthermore,by compensating the power of the CIR estimated in the specific segmentwithin the extrapolation section through extrapolation, so that theproportional relation between the power of the signal measured in thespecific segment and the power of the CIR generated in the specificsegment through extrapolation can become identical to the proportionalrelation between the power of the signal and the power of the CIR bothmeasured in the training section, problems of unintended increase ordecrease in signal power, which is estimated in the extrapolationsection through extrapolation, may be reduced.

The present invention is even more effective when applied to mobile andportable receivers, which are also liable to frequent change inchannels, and which require strength (or robustness) against intensenoise.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

The invention claimed is:
 1. A method for processing a digital broadcastsignal at a transmitter, the method comprising: formatting the datagroup including mobile service data, wherein formatting the data groupcomprises: mapping the mobile service data into a data group; addingtraining sequences into corresponding locations of the data group,wherein at least 5 of the training sequences are spaced M segments apartin the data group, wherein at least 1 of the training sequences isinserted between a first training sequence and a second trainingsequence of the at least 5 training sequences, and wherein M is aninteger; adding signaling data into the data group, wherein thesignaling data are added between the first training sequence of the atleast 5 training sequences and the at least 1 of the training sequences;inserting place holder bytes for MPEG header and non-systematicReed-Solomon (RS) parity into the data group; and deinterleaving data inthe data group; non-systematic RS encoding the mobile service data inthe formatted data group to insert the non-systematic RS parity intolocations where the place holder bytes for the non-systematic RS paritywere inserted in the formatted data group; and transmitting a digitalbroadcast signal including the non-systematic RS-encoded mobile servicedata.
 2. The method of claim 1, further comprising: Interleaving thenon-systematic RS encoded mobile service data.
 3. The method of claim 1,wherein: the at least 1 of the training sequences in the digitalbroadcast signal has a first K-symbol sequence and a second L-symbolsequence; K is identical to L; and the first K-symbol sequence and thesecond L-symbol sequence have a same data pattern.
 4. The method ofclaim 1, wherein the at least 5 of the training sequences in the digitalbroadcast signal have a same data pattern in common.
 5. An apparatus fortransmitting a digital broadcast signal, the apparatus comprising: agroup formatter configured to format a data group including mobileservice data, wherein the group formatter is further configured to: mapthe mobile service data into a data group; add N training sequences intocorresponding locations of the data group, wherein at least 5 of thetraining sequences are spaced M segments apart in the data group,wherein at least 1 of the training sequences is inserted between a firsttraining sequence and a second training sequence of the at least 5training sequences, and wherein M is an integer; add signaling data intothe data group, wherein the signaling data are added between the firsttraining sequence of the at least 5 training sequences and the at least1 of the training sequences; insert place holder bytes for MPEG headerand non-systematic Reed-Solomon (RS) parity into the data group; anddeinterleave data in the data group; a non-systematic RS encoderconfigured to non-systematic RS encode the mobile service data in theformatted data group and to insert the non-systematic RS parity intolocations where the place holder bytes for the non-systematic RS paritywere inserted in the formatted data group; and a transmission unitconfigured to transmit a digital broadcast signal including thenon-systematic RS-encoded mobile service data.
 6. The apparatus of claim5, further comprising: a data interleaver configured to Interleave thenon-systematic RS encoded mobile service data.
 7. The apparatus of claim5, wherein: the at least 1 of the training sequences in the digitalbroadcast signal has a first K-symbol sequence and a second L-symbolsequence; K is identical to L; and the first K-symbol sequence and thesecond L-symbol sequence have a same data pattern.
 8. The apparatus ofclaim 5, wherein the at least 5 of the training sequences in the digitalbroadcast signal have a same data pattern in common.